Chinese Medicine Demystified (Part V): A Closer Look At How Acupuncture Relieves Pain

pain

Note: This is the fifth article in an ongoing series. If you haven’t read the first four, I recommend doing that before continuing:

In this article we’re going to take a closer look at one of the latest theories on how acupuncture relieves pain. I’m going to break it down in plain language for my readers who don’t have a scientific background, but I’ll also provide references at the end of the article for those of you that want the nitty-gritty detail.

Keep in mind that pain research is a constantly evolving topic, and more is being learned each year about the mechanisms of pain relief via acupuncture. (Although as an interesting side note, according to Professor Bruce Pomeranz of the University of Toronto, we know more about acupuncture analgesia than many chemical drugs in routine use. For example, we know little about the mechanisms of most anesthetic gases but still use them regularly. 1)

What I’m going to share with you here represents the latest information from the American Academy of Pain Management and papers published in major peer-reviewed journals.

The physiology of pain

Before I explain the mechanism, I have to give you a little background on the physiology and neurology involved.

There are two types of nerves involved in our perception of pain: sensory (nocioceptive) and position (proprioceptive) nerves. Both of these nerve types are firing at the same time in an area where we’re experiencing pain. These nerves travel to the spine and pass their information on to neurons in the spinothalamic tract. This tract travels up the lateral dorsal horn of the spinal cord to the mid-brain.

The sensory nerves register pain. The position nerves tell the brain where that pain is coming from. So the sensory nerves say “ouch!” and the position nerves say “my knee!”.

There are two different types of sensory nerves involved in the acupuncture response. There are A-Delta fibers, which transmit sharp, burning pain messages. And there are C-fibers, which transmit dull, throbbing pain messages. A-Delta fibers are responsible for acute pain, and the signals they send are short-lived. They fire for a while and then the signals die off. C-fibers are responsible for chronic pain, and fire over an extended period of time.

A-Delta fibers are surrounded by a fatty, myelin sheath and the signals they send travel at 60 ft/second (that’s fast!). C-fibers are unmyelinated and their signals travel at 20 ft/second.

The A-Delta fibers mediate what is known as the “gamma loop”. The gamma loop is what gets activated when you stick your hand in a fire and your hand jumps back. These nerve fibers respond so quickly that your hand is immediately pulled back out of the fire. Chronic pain is a C-fiber problem, so C-fiber signals don’t travel quite this quickly.

Now, if the signal strength of the position nerves (the ones that register the location of pain) is what it’s supposed to be, the brain will release powerful natural pain relieving substances called enkephalins when it starts to receive those C-fiber messages. The enkephalins then plug up pain receptor sites in the brain, spine and capillary beds where the pain is located. This stops the pain in its tracks.

When things go wrong

Unfortunately, this is not what happens in people with chronic pain. Why? The current explanation is that the position nerve signal going up to the brain is too weak. The mid-brain can’t figure out where the pain is coming from, so the enkephalins don’t get released. This is why people in chronic pain often have trouble identifying exactly were the pain is. The neural threshold of the position nerve pathway is too low, so these people aren’t getting a clear signal where the pain is emanating from.

Because the brain isn’t getting the message, the nerves keep firing. And keep firing. After a while the nerves become inflamed, which in turn further weakens the signal’s ability to jump the threshold and get the message to the brain.

So that’s the first problem. The nerve signals are too weak and aren’t stimulating the brain to release the natural painkillers.

The second problem involves a survival mechanism that the brain evolved a very long time ago. Let’s take a knee injury as an example. When we bang our knee into something, the brain immediately takes measures to protect it. The brain doesn’t know what happened to the knee, but it assumes a worst-case scenario. Maybe you were bitten by a poisonous snake, or perhaps you seriously cut your knee and are losing a lot of blood.

What the brain does in this situation is restrict the blood supply going into the knee and the blood return coming out of the knee. This is actually a very intelligent choice. If you were bitten by a venomous snake, reducing blood flow around the knee will lessen the chance that the poison will spread. And if you were cut badly, reducing the blood flow will lessen your chances of bleeding to death.

This phenomenon is known as “guarding”. One of the results of reducing blood flow to the knee is that it becomes stiff and weak (sound familiar?). The brain wants it to feel weak because it is attempting to protect the knee. The brain doesn’t want whatever happened to the knee to threaten your chances for survival. So the brain sacrifices the health of the knee in order to keep you alive.

This was a great strategy before the advent of western emergency medicine. Almost everyone would prefer to lose function in their knee to death. But this isn’t a choice most of us have to make anymore, because when we cut our knee or get bitten by a snake we can go to the hospital and they can save our lives. And the problem is that cutting off blood flow to the knee – while it may have saved our lives in times past – dramatically limits the knee’s ability to heal.

Why? Because everything we need to heal is in the blood. The blood contains analgesics (painkillers), anti-inflammatories, nutrients absorbed from food, oxygen, hormones and immune substances to fight infection. If the blood flow is restricted to a particular area, healing won’t occur. No blood flow, no healing.

Stop and think about this for a minute. It’s such an obvious fact that it’s often overlooked in medicine. It’s not taught in such a direct way in medical school, but when I’ve explained it to a couple of doctors they both said something to the effect of, “Huh. I never thought of it that way, but it makes perfect sense.”

How acupuncture helps

Okay, now we’re finally coming to the part where I explain how acupuncture fits into this picture. Inserting needles into the skin at peripheral sites “jumps” the neural threshold on the position nerve pathway, so that the signal can reach the brain. Once the signal reaches the brain, the whole series of events I described in the paragraphs above kicks in. The brain recognizes there is pain and where it’s coming from and releases enkephalins (painkillers).

This initial response is very fast. It should be perceived as almost instantaneous by the patient. But after the needling therapy the patient goes home and the pain comes back. The old bad habit of the nerve chronically firing below the threshold re-establishes itself. The body, just like the mind, has a hard time breaking bad habits.

But if the patient returns in a couple of days to get another treatment, the neural threshold will be jumped again. And if you keep jumping the neural threshold, eventually the central and peripheral nervous system figure out that it’s better to operate in the non-pain state than in the pain state. The technical term for this is re-establishment of neurological homeostasis.

Once this happens, the brain is no longer receiving pain signals from the knee. It no longer thinks the knee is injured or threatening the survival of the body. Now, instead of restricting blood flow to the knee, the brain does the opposite. It immediately vasodilates the capillaries and venules around the knee, which increases blood flow and begins the healing process.

What I’ve described above is how acupuncture relieves pain via the peripheral and central nervous system. There’s another pain relief mechanism that involves activating the immune system. Acupuncture needles are seen as foreign invaders to our body. Inserting a needle into the skin creates a micro-trauma that in turn stimulates the activity of immune cells that control inflammation.

There are millions of immune cells called mast cells in the dermis of the skin. These cells are like water balloons full of fatty molecules called leukotrienes and prostaglandins A & B. When a needle is inserted into the skin, it pops the mast cells and releases the leukotrienes and prostaglandins. Prostaglandins cause the cutaneous nerve in the area to fire (which activates the process described in the previous paragraphs). Leukotrienes are the strongest anti-inflammatory substance the body can produce.

Leukotrienes cause local capillaries to vasodilate and become permeable. White blood cells called macrophages leak out through the capillaries and immediately begin to heal the damage caused by the needle stick.

However, the healing caused by the needle insertion isn’t limited to the damage caused by the needle. If there is other damage in the area from previous traumas or injuries, that will also be addressed by the immune chemicals released by the needle insertion.

What’s more, the micro-trauma caused by the needle starts a systemic immune response. This promotes healing of the soft tissue throughout the body – not just at the needling site. After the needles are removed, the needle-induced lesions continue to stimulate the body until the lesions heal. This means that the anti-inflammatory effect of acupuncture persists for 2-3 days (and sometimes as long as a week) after the needle is withdrawn.

Summary

Genetically the body is not designed to be in chronic pain. It will do everything it can to get us out of pain. Acupuncture “reminds” the body how it should be functioning, and helps its powerful inbuilt pain relieving mechanisms kick into gear. It’s a bit like jump starting a car. You’re not changing how the car works, or even adding anything to the engine. You’re just giving the battery a little jolt so the car can run how it’s supposed to.

It’s important to understand that this neurochemical mechanism not only provides pain relief, but also promotes homeostasis and tissue healing and regulates the immune, endocrine, cardiovascular and digestive systems. This explains why getting acupuncture treatment for your knee pain also addresses other problems you might have, such as asthma, irritable bowel, high blood pressure, anxiety and insomnia.

In the next and final article of this series, I’ll explain the advantages of Chinese medicine over western medicine for the prevention and treatment of most common health conditions.

Recommended resources for more information

  1. Pomeranz B. Acupuncture analgesia – basic research. In Stux G, Hammerschlag R, editors: Clinical acupuncture scientific basis. Berlin 2001. Springer.

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Comments Join the Conversation

  1. Jasmin says

    Oh no! It was going so well! I was going to forward this to my colleagues, but then you made some errors, and as we know, small errors make people suspicious and likely to ignore big truths. Leukotreines are PRO-inflammatory. The process you described of white cell recruitment and margination is one of the steps of inflammation. In fact, everything you described, is actually inflammation. The increased vasodilation and permeability of the capillaries is what gives us the heat and swelling of inflammation. The swelling and release of white cell inflammatory markers stimulate merkel cells to release pain signals via their synaptic connection to dermal afferent nerves. The increased metabolic activity of immune cells and their released chemicals of recruitment also contribute to the heat associated with inflammation. That’s ok though, because what you have said is true, the process of inflammation is actually the body’s repair system, the recruitment of macrophages and neutrophils to phagocytose invading organisms and damaged cells, the increased blood flow to provide metabolic components to fuel rapid tissue repair. When it’s working well, it’s a good thing. My undergraduate degree was in Acupuncture, and I’m currently doing graduate-entry Medicine/Surgery. What you have said makes a lot of sense and I have really enjoyed the series.

  2. john says

    Well, ok, but why can needling LI 11 take away knee pain (especially at Liv 8, St 35 and K 10)? Why can needling K3 on one side and Bl 65 on the other effectively relieve back pain along the whole Bl channel (if I’m allowed that terminology). Can you really explain that without using the concept of the channels?

  3. michael peluso says

    “Leukotrienes are the strongest ANTI-inflammatory substance the body can produce.”

    Leukotrienes are NOT ANTI-inflammatory molecules, they are PRO-inflammatory molecules and a necessary part of the immune response.

  4. Mark Mandel says

    (slight fix in the quoted HTML)
    I’m using Firefox 3.6.3 in WinXP + SP3.
    BTW, your comment, sent to me in gmail, had all the HTML code exposed, not rendered. Like so (I’ve changed the angles to square brackets):
    Author: Chris Kresser
    Comment:
    [p]The list works fine for me:[/p]
    [p][ol]
    [li]This[/li]
    [li]is[/li]
    [li]a [/li]
    [li]test.[/li]
    [/ol]
    [div]As does the [span style="text-decoration: underline;"]underline[/span] and [span style="text-decoration: line-through;"]strikeout[/span].[/div]
    [div][/div]
    [div]What platform are you using?[/div]
    [/p]
    Oh, I hate this sort of thing, and it happens all the time. Not just to me, I mean.

  5. Mark Mandel says

    I’m using Firefox 3.6.3 in WinXP + SP3.
    BTW, your comment, sent to me in gmail, had all the HTML code exposed, not rendered. Like so (I’ve changed the angles to square brackets):
    Author: Chris Kresser
    Comment:
    [p]The list works fine for me:[/p]
    [p][ol]
    [li]This[/li]
    [li]is[/li]
    [li]a [/li]
    [li]test.[/li]
    [/ol]
    [div]As does the [span style="text-decoration: underline;"]underline[/spanand [span style="text-decoration: line-through;"]strikeout[/span].[/div]
    [div][/div]
    [div]What platform are you using?[/div]
    [/p]
    Oh, I hate this sort of thing, and it happens all the time. Not just to me, I mean.

  6. Chris Kresser says

    The list works fine for me:

    1. This
    2. is
    3. a
    4. test.
    As does the underline and strikeout.
    What platform are you using?

  7. Mark Mandel says

    BTW,

    why does this comment form have icons for lists if they don’t make lists?
    And let’s test the

    bold,
    italic,
    underline, and
    strikeout icons as well.

  8. Mark Mandel says

    Slow down a bit there,  Skeptic, your typing fingers are running on ahead of your brain, or else you edited too fast. I’d bet dollars to donuts that you’re confusing nerves with nerve signals, in your text if not in your mind. Quoting you:

    There are two different types of sensory nerves involved in the acupuncture response. There are A-Delta fibers, which transmit sharp, burning pain messages. And there are C-fibers, which transmit dull, throbbing pain messages. A-Delta fibers are responsible for acute pain, and are short-lived. They fire for a while and then die off. C-fibers are responsible for chronic pain, and fire over an extended period of time.

    Do you really mean that an A-Delta fiber is short-lived and dies soon after it transmits a pain signal? It seems much more likely that the signal carried by an A-Delta fiber is short-lived and dies off quickly.
    Similarly, immediately after that:

    A-Delta fibers are surrounded by a fatty, myelin sheath and travel at 60 ft/second (that’s fast!). C-fibers are unmyelinated and travel at 20 ft/second.

    Damn, how do either of them stay in our bodies? Again, it’s the signals that travel at these rates, not the nerves that carry them. The nerves are the tracks, the signal is the train.
    I’ve been reading this article with interest, but now your carelessness is making me cautious.
     

    • Chris Kresser says

      Mark,

      I meant to describe the signals sent by those fibers, not the fibers themselves. Thanks for catching the mistake.

  9. Jesse says

    “RCTs have no way of controlling for these variables and they don’t even try to.”

    What is the randomization for, then? If the sample size is large enough, it should work out that there are about the same number of people who eat well, exercise, and get sleep, so if the acupuncture works, those people should be affected by it enough to distinguish it from the controls. Right?

  10. Jesse says

    I disagree, Matto: placebo acupuncture is not easy to do, at least not in a blinded manner. The person giving the treatment can easily tell whether the needles they are using are puncturing the skin or not, assuming they’re using the fake needles. Still, it seems like that should increase the apparent efficacy of the real acupuncture, if anything, so studies that show that it is no better than placebo might still be worth something… of course, it is claimed that even poking people with toothpicks is still real acupuncture.

  11. Matto says

    If Acupuncture can treat or cure any given illness, then this is easily prove-able. At some point along the timeline, a given practitioner or group of practitioners will be able to isolate who has said condition and design a placebo controlled study. This has already been done. As placebo acupuncture is easy to do. There has never been a successful study like this that can be replicated. There have been many attempts, including the famous post partem depression studies and many many others. It has proven so completely impossible to demonstrate acupuncture’s effectiveness , that it is quite hard to get acupuncturists to participate these days. You can find many studies that seem to show the effectiveness of Acupuncture vs placebo Acupuncture, but if you look deeper, you will find many cases where the study was repeated by others and failed repeatedly. I did extensive research on the topic, originally hoping to find the opposite result. Don’t kill the messenger, I am truly just stating the facts of the matter, you can see for yourself.

    • Chris Kresser says

      Matto,

      Thanks for your comment.

      Acupuncture has the potential to treat or cure any illness. But this is only true insofar as the human body has that potential, since acupuncture works by stimulating innate healing mechanisms. This means that acupuncture’s ability to treat or cure illness is dependent upon the status of the person being treated. If their self-repair mechanisms are significantly damaged in some way, acupuncture will not be able to address their condition.

      For this same reason (and several others), acupuncture research is difficult. Healing never takes place in a vacuum. If two study subjects receive the same acupuncture treatment, but one is eating well, exercising, and getting plenty of sleep, while the other is eating junk, not exercising at all, and sleeping 4-5 hours a night, who do you think will improve? RCTs have no way of controlling for these variables and they don’t even try to. This highlights the fundamental difference, once again, between holistic and allopathic medicine. In holistic medicine we consider not only the physiological functioning of the entire body, but also the effects environmental factors, nutrition, exercise, stress, emotional and psychological state, etc. In allopathy, the focus is usually on chemically altering the function of one part of the body without regard to the influence of the rest of the body or the other factors I just mentioned.

      What I’m suggesting is that together with an appropriate diet, stress management, exercise, and other aspects of a healthy lifestyle, acupuncture makes far more sense as a preventative care modality and a means to address mild to moderate imbalances than surgery and drugs.

    • Chris Kresser says

      Matto,

      I forgot to mention, a new study was just published that addresses your question directly and reaches a different conclusion. From the abstract:

      We reviewed the available literature for different placebos (sham procedures) used to control the acupuncture effects, for moderators and potential biases in respective clinical trials, and for central and peripheral mechanisms involved that would allow differentiation of placebo effects from acupuncture and sham acupuncture effects. While the evidence is still limited, it seems that biological differences exist between a placebo response, e.g. in placebo analgesia, and analgesic response during acupunture that does not occur with sham acupuncture. It seems advisable that clinical trials should include potential biomarkers of acupuncture, e.g. measures of the autonomic nervous system function to verify that acupuncture and sham acupuncture are different despite similar clinical effects.

      After reviewing the available literature, these authors did find a biological difference between acupuncture and sham acupuncture. I think the jury is still out on this question.

  12. says

    Again, Chris and I would differ in opinion on this one.  I’d have to get my copy of Huangdi Neijing and Zhenjiu Jiayijing to be sure though..
     
    What I’d like to say though, is that there should be many ways of looking at the same thing, in order to achieve a better understanding.  (just not the “energy meridian”… )

    • admin says

      Who knows? There may be a correlation. But as I explained in the second article of the series, I think the ancient Chinese were referring to blood vessels. Keep in mind that the word “meridian” and their particular arrangement on the body was an invention of Soulie de Morant in the early 1900s. The meridians as we know them today aren’t found in classic Chinese texts.

  13. Jesse says

    Okay, that’s what I thought you were saying. Thanks for answering my questions. At this point it sounds like I would prefer toothpick treatment if I were ever to get acupuncture, as it sounds more pleasant, though I’m sure your experience suggests that it wouldn’t work as well, hehe.

  14. admin says

    Jesse, you’re combining two mechanisms into one.  The first involves stimulating the peripheral nervous system to “jump” the neural threshold so the brain will begin releasing painkillers.  The second involves the local inflammatory response that occurs when a needle punctures the skin.  We might expect actual needling to provoke a stronger response in the second case, but in the first it’s possible that a toothpick pressed against the skin may have a similar effect.

  15. says

    Jesse, actually just touching your skin against something causes capillaries to burst.  It’s just that our bodies are quite efficient in immediately repairing the damage.  If not, we’d have bruises all over.

  16. Jesse says

    So toothpicks induce A-Delta fiber firing without penetrating the skin? If I read the original post correctly, that was one of the two mechanisms you proposed for how acupuncture works: Needling causes micro-traumas that induce the brain to release painkillers and allow the old injury to heal. Do toothpicks cause micro-traumas?

  17. admin says

    Jesse,

    Only one of the mechanisms I described (local tissue inflammatory response) absolutely requires puncture of the skin.

    There are studies showing non-penetrative stimulation of points is as effective as penetrative acupuncture, and some that don’t.  The jury is still out.

  18. Jesse says

    Chris and Philip,
    At this point, I’m not suggesting that acupuncture, whether with needles or toothpicks, has no effect.
     
    However, I thought the point of this article was to suggest a possible mechanism for the effects of acupuncture: that needles damage the skin, inducing release of painkillers, and that they stimulate the immune system, which helps healing and stuff.
     
    It seems like these effects are dependent on the puncture of the needle, which toothpicks would not provide. So if toothpicks still work as well as needles, doesn’t this suggest that your mechanism is wrong?
     
    That’s my concern at the moment. I think it would be good to discuss placebo at some point too, but I understand you’re planning some future posts on the subject, so I guess I’ll wait until then.

  19. admin says

    Jesse,

    The following is an excerpt of a response I wrote to someone who claimed that acupuncture was “worthless” because it doesn’t outperform sham acupuncture (so-called placebo) in many clinical trials.  I’m not saying you’re suggesting that, but my response to him applies here as well.

    Here’s the short version: what we refer to as “placebo effect” should more accurately be called “self-healing”.  Placebo effect involves known physiological effects, including the release of endorphins in the brain.  To the body, placebo is just as real as any other “active treatment” that releases endorphins.  The end result is the same, except that in the case of placebo, there are far fewer side effects and risks.

    I think healthcare practitioners of every type should be doing everything they can possibly do to invoke the self-healing (i.e. placebo) response.  Why wouldn’t we? Studies show it accounts for approximately 30-50% of most treatments, and sometimes as much as 100%.  And that makes sense if you understand the holistic nature of the body and how it heals.

    Read more below.

    ———————————————–

    I agree that the literature doesn’t support the idea that point selection matters, or that needling technique makes a difference, or that even breaking the skin makes a difference. However, I’ll also say that just because the literature doesn’t yet support a difference that doesn’t mean there isn’t one. As I pointed out earlier most studies on acupuncture are underpowered because sample sizes are based on the assumption of a 30% placebo effect, which is unsound.

    You say that stimulating the skin without breaking it is not acupuncture. Perhaps not as it’s defined on the west. But here we have another mistranslation. Jesuit monks living in China translated the character “zhenzi” as “acupuncture”. Acus (needle) punctura (puncture). A more correct translation of the term is needle therapy. Sometimes the Chinese punctured the skin and left the needles there. Sometimes they used them for bloodletting. (Before you dismiss bloodletting as hopelessly archaic, keep in mind that it’s still used in modern medicine today. In fact, a fairly recent study showed that leech therapy [bloodletting] was more effective than surgery for osteoarthritis of the knee.) In Japan, some styles don’t puncture the skin at all.

    My disagreement with you is on the nature, meaning and clinical significance of placebo.

    Last week a patient came in to the clinic with a history of severe acid reflux / GERD. He had an h. pylori infection with ulcer about twelve years ago, and since then he’s had intractable reflux. He’s been treated with all of the PPIs and H2 blockers, has seen numerous doctors and has tried several different special diets. Nothing helped. As a last resort he came to try acupuncture. This was a difficult decision for him because he works as a research scientist. He came in saying “I don’t believe in this stuff, but I don’t want to have surgery so I’m willing to try it.” Fair enough, I said. Let’s give it a shot.

    After four acupuncture treatments his symptoms have improved by 80%. For the first time in twelve years he is able to eat without having heartburn afterwards. And he’s been able to completely get off his medication.

    You may argue that this is “placebo”. You may be right. But I say, “so what”?

    What my patient is concerned with is getting rid of his problem. The western drugs, which arguably have a stronger placebo effect than acupuncture because of the widespread cultural belief in their effectiveness, weren’t able to help. Acupuncture has almost completely cured his problem in just two weeks. Do you think he cares whether it’s “placebo” or “active treatment”?

    Experiences like this are common in the clinic. That’s why more and more people are getting acupuncture, in spite of what the clinical research shows or doesn’t show. People want to feel better and address their health problems, and acupuncture helps them do that.

    I’m sorry this is so long but I still have a few points to make. My argument, as I already stated above, is that the concept of placebo has probably outlived its usefulness. Why? Because defining it in a consistent way that distinguishes it from specific treatment effects seems impossible. We should instead be focusing on the choice of outcome measure and the magnitude of the effect, rather than on interventions that are difficult to define.

    As an example, when compared with usual obstetric care, the presence of a support person during labor has dramatic effects on the use of analgesics, anesthesia, episiotomy, and cesarian section and the incidence of severe postpartum depression. (http://www.ncbi.nlm.nih.gov/pubmed/10796179)

    What do we call the additional effect of a support person, which are clearly measurable and are clearly producing real physiological changes? Do we call it placebo? Why? How is that distinguishable from the effects of the other methods of obstetric care?

    The answer is that it’s only distinguishable by the name and meaning we’ve applied to those effects. We’ve decided that they are secondary (and by implication less important) than the effects of the treatment being primarily studies. But I assure you that from the patient’s perspective (and one would hope the doctor treating her) those so-called “placebo” effects are no less significant in the outcome.

    Let me pose a hypothetical question for you. Say you could choose between two treatments for a particular condition. Both of these treatments have roughly the same outcome in clinical studies. However, one treatment carries significant side effects and risks, including irreversible physiological damage that in fact perpetuates and worsens the problem you sought help for. The other treatment is relatively free of side effects and risks, is well tolerated, and does nothing but improve your problem.

    Which would you choose?

    The scenario above is not hypothetical. It describes the choice a patient with depression has when deciding between an SSRI or a sugar pill. Sapirstein and Kirsch conducted a meta-analysis of 3,000 patients who received either antidepressants, psychotherapy, placebo or no treatment at all. They found that 27% of therapeutic responses were attributable to drug activities, 50% to psychological factors, and 23% to “non-specific” factors. In other words, 73% of the response to the drug was unrelated to its pharmacological activities – and antidepressants may be no better or more specific than placebos. (Read this article for more info: http://chriskresser.com/antidepressants-not-as-effective-as-research-suggests)

    If you’re going to be consistent with your terminology, you’ll have to refer to antidepressants (and some other commonly used drugs) as placebos. They are no less of a placebo than acupuncture is according to the research.

    Some doctors are in fact aware of this, and yet they go on prescribing them. They argue that the benefit of recovering from depression outweighs the ethical considerations of prescribing a placebo without the patient’s knowledge. Doctors are willing to do this in spite of the fact that these “placebos” (active drugs, in this case) have serious side effects and risks.

    If it were me, I’d take the placebo, thanks. I’ll get the same improvement without any of the risks.

    This is why I asked you what your definition of placebo is. The terminology is important here, because what you refer to as placebo is in fact a measurable treatment effect with a significant clinical outcome.

    Moreman and Jonas suggest what I believe is a more useful term, which is “meaning response”. They define the meaning response as “the physiologic or psychological effects of meaning in the origins or treatment of illness.” (http://www.annals.org/content/136/6/471.full) They provide many examples where the meaning ascribed to a treatment produces different outcomes.

    One of my favorites is a study in which 835 women who regularly used analgesics for headache were randomly assigned to one of four groups. One group received aspirin labeled with a widely advertised brand name. The other groups received the same aspirin in a plain package, placebo marked with the same widely advertised brand name, or unmarked placebo.

    In this study branded aspirin worked better than unbranded aspirin, which worked better than branded placebo, which worked better than unbranded placebo. Aspirin relieved headaches, but so does the knowledge that the pills you are taking are “good” ones. (http://bit.ly/9JxGe0)

    It is also known that placebo and acupuncture analgesia elicit the production of endogenous opiates. In both cases the analgesic effect can be blocked with injection of nalexone.

    So, to say that a treatment such as acupuncture “isn’t better than placebo” does not mean that it does nothing. Nor does it mean that acupuncture doesn’t improve clinical outcomes. Nor does it mean that acupuncture is not a better choice than another treatment with similar outcomes, when all factors are considered (side effects, risks, complications, etc.)

    In any event, while the research community goes on insisting that acupuncture is “just placebo” (an inane statement that reflects a lack of understanding of the nature and value of placebo), I will go on giving my so-called “placebo” treatment to patients and improving their health and quality of life.

    I leave you with a quote:

    “Most of us have been taught that western medicine is based on science, and science represents the unbiased, objective way to search for truth. However, subjective judgments lie behind all the facets of “scientific” research. (Not to mention that nowadays, most clinical research are funded by pharmaceutical companies)

    All data are theory-, method-, and measurement-dependent. That is, “facts” are determined by the theories and methods that generate their collection; indeed, theories and methods create the facts.

    This means that how the problem will be defined, which model(s) of inquiry will be considered to be relevant to the problem as defined, which model(s) of inquiry will be considered to be relevant to the problem as defined, where one shall look (and, by implication where on shall not look) for evidence–and even what one shall consider to be constitutive of evidence–are all determined by the paradigmatic “map” or world view to which the scientist is committed.”

    –John Ratcliffe, Notions of validity in qualitative research methodology

  20. says

    @Jesse
    According to classical meridian theory the meridians are like major vessels and the collaterals link them together.  The whole body system is covered by them.  It is similar to how you have major arteries and veins, then smaller ones, down to capillaries, yet every nook and cranny of the body is reached by it.
    Hence, according to Sun Simiao (if memory serves me right),  if there is pain, there is an acupuncture point.  These are called locus dolendi or “ah shi” points.  What can be deduced from this is that sticking a needle anywhere can have an effect.  The points are just places where effects are more profound imho.
    Now, there are many ways to influence these points and meridians.  Acupuncture is one.  Others include moxibustion and tui na massage.  Think about it, in tui na you use touch to stimulate these points, and they also work.  Moxibustion may not even have actual physical contact with the patient, but there is a physiologic reaction to the heat and volatile oils released.  My point is traditional chinese medicine recognizes that acupuncture is not the only way to stimulate points and elicit reactions.  Even simple touch can do.  Given this, then even “fake” acupuncture can be as effective (at times) or only slightly less effective (sometimes even more) because it’s not how the stimulation occurs, it’s the fact that stimulation does occur.
    So why use needles?  If I want to hit eight points at once with only two hands, you can see how using needles makes treatment more efficient and less tiring than my hands and fingers!  It also enables me to treat more than one patient at a time.  From experience, using needles is sometimes less painful for the patient from using finger pressure to reach points, LI 4 and LIV 3 come to mind…

  21. Jesse says

    What I meant was, fake acupuncture using toothpicks is just as effective as any kind of needling, or any kind of needling is no more effective than fake acupuncture.

  22. Jesse says

    What do you think of this study? It seems like a good one: large size, decently done, published in a respectable journal. But it shows that fake acupuncture using toothpicks is no more effective than any kind of needling.

  23. admin says

    I don’t know much about reflexology as a system, and am not planning any articles on it.

    Thanks for your feedback, Tim!

  24. Tim says

    Now that you so brilliantly demystified acupuncture, what do you think of reflexology? Can you demystify that as well? Is that a part of chinese medicine as well or is that a western invention?

  25. Donna Chang says

    “Because we practice in an environment dominated by evidence-based medicine.” True, and again, context is everything.  

    Chris, we may not agree on all points and that’s fine with me. I am glad to hear that your article is bringing more people to try acupuncture. That’s a really good thing. This discussion has prompted me to start reading the Dao of Chinese Medicine. When I can overlook Kendall’s occasional opiniated and dogmatic tone, I can see that there is a lot to learn from his interpretation. I think it is possible to discuss chinese medicine in terms of physiology without being dogmatic about it. It is also interesting to read Manaka’s Chasing the Dragon’s Tail, (which I highly recommend even if you don’t practice his method,) for a different viewpoint. I think it would be interesting to have this conversation again in 20, 30 years’ time to see what new breakthrough in the western medicine can shed more light on the subject. The fascinating thing about chinese medicine is that many new principles and findings in biophysics/physics/biochemistry was actually already mentioned in the ancient texts!

    I appreciate your effort in writing this articles and the discussions. See you in school!

  26. admin says

    Touch also stimulates oxytocin release.  Oxytocin plays a major role in regulating the parasympathetic nervous system.  Although it’s commonly known for its effects in childbirth and lactation, it’s range of action is much larger.

    All mammals, with the exception of humans now, have extensive grooming rituals. There’s a lot of physical contact during grooming, and that has a calming effect on the nervous system.  This is one reason why any therapeutic modality involving touch – including acupuncture – can be so powerful.  The desire for touch is in our genes.

  27. says

    My theory about why touch already has an effect is this: acupuncture can be considered a form of really really really deep tissue massage (think about it) and in some patients, just a light touch can already stimulate the same receptors that acupuncture needles stimulate.
    TCM wise, the theory of meridians and collaterals infers that Qi and Blood ultimately cover the whole body – so hypothetically inserting a needle or applying pressure anywhere can have an effect.

  28. admin says

    As Philip has mentioned, it’s refreshing to have an intelligent conversation about this stuff.

    Donna, it is becoming increasingly accepted in the research community that so-called “sham” acupuncture (that doesn’t penetrate the skin) has a biological effect. I have a book on the biophysics of energy medicine, so I’m familiar with the potential mechanisms for contact needling that you describe.  However, it’s also possible that simply stimulating the surface of the skin with a needle is enough to activate the nerve impulse, which in turn would be enough to begin the cascade of neuroimmune responses I’ve described in previous posts.

    Even acupressure and massage can be explained physiologically.  It’s not really a mystery at all.

    I’m not making the claim that biomedicine can explain everything that happens under the frame of Chinese medicine.  But I am arguing that the general mechanisms are fairly well understood, and that they don’t depend on the mistaken idea that energy is circulating through the body.  Energy doesn’t circulate.  The potential for energy does.

    I think we need to be aware of the research and find ways to validate acupuncture’s effectiveness within the existing framework.  Why?  Because we practice in an environment dominated by evidence-based medicine.  Obama recently announced that he’s interested in incorporating acupuncture into the healthcare system.  But he specifically added a caveat – that we need more research first.

    Sure, we’ll always be able to help the people who are interested in acupuncture. But if we want to move beyond that 1.5% of the population (a pitifully small number), we have to find some common ground.

    I’m interested in helping as many people as I can with this remarkable medicine. That’s why it’s so important to me to find ways to talk about it with people that get them interested and excited.  That’s what these posts have been about.

    I’m glad they’ve had some effect.  I’ve received 10-12 requests for referrals to acupuncturists in various parts of the country from readers.

  29. Donna Chang says

    There are many issues to discuss here, not just one. I probably can’t get into discussing some of it without opening some other cans of worms. :-)
     
     Chris, I am not saying outcome or symptom reduction don’t matter, or that current research methods have absolutely no value in evaluating acupuncture. Current research methods have some value if you can see it for what it is–the context of it, the paradigm in which it is based on, notice what it omits, and the underlying limitations, instead of believing that is the objective whole truth.
    Right now, most studies in medicine are quantitative research. Because of the holistic nature of Chinese medicine, I would like to see more qualitative research being done. I don’t have an idea how it should be done, as designing studies has not been my area of focus. I would leave it to people who are more inclined to do so. 
     
    On the problem of current acupuncture studies:  some “sham” acupuncture in researches use non-penetrating needle to stimulate a acupuncture point. However, many Japanese blind acupuncturists use non-penetrating “contact needles” in acu treatments. Dr. Bear, whom I studied with, uses such method, and I have witnessed its effectiveness. Sometimes, when I am deciding on which points to select, I would test them by placing my finger lightly on one point at a time. Patients can usually tell me which point has better effect on their pain, breathing etc. 
     
    So yes, even just placing my finger on an acu point can elicit a immediate response from the body. How can that be explained? 
    There are many ways to understanding the body that goes beyond the biochemistry model of western medicine, and actually more based on the 20-21st century modern physics findings, some look into the bioelectricity and electromagnetic field generated by the body (e.g. <i>Root of Chinese Qigong</i> by Dr. Yang Jwing Ming), some focuses on the signal system functions derived the way our body is organized and developed since it’s embryonic stage, (<i>Chasing the Dragon’s Tail </i> by Yoshio Manaka, MD, which I just started reading, fascinating work so far) some look at how universe is entirely holographic in nature, including our body (<i>Holographic Universe</i> by Michael Talbot), etc. etc.
    Philip, I agree  on the value of being open-minded and exchanging idea. There is a fable of the 3 blind people who never encountered an elephant before. One day, there is an elephant in town, they all touched a very different part of the elephant and drew a different conclusion of what an elephant is like, and started arguing with one another and insisting the others are wrong, and their own idea of the elephant is the only truth. 
    They would have learned from each other if they can just be open-minded and discuss more openly. 
    Jesse, I hope this is not too overwhelming. It has taken me many years of thinking/ learning about the subject of healing, what I found is a web that everything is connected with everything else, and that’s why it is hard to just talk about one thing without mentioning all other things. 
    “Defining what a healthy human being is seems like a good idea. How does one go about doing that?” This is entirely subjective. We can go on and go about what makes us healthy or not, but in the end, it is your direct experience that counts most. 

    Chris, thanks for mentioning the importance of meaning response, and that one of the important advantage of acupuncture is that it is low-risk with little side effects. I completely agree with that.

  30. says

    This is the benefit of open discussion and open minds: we exchange ideas, clarify misconceptions, etc etc. =)
     
    Yes I am aware of those studies involving sham and active acu.  I’ve blogged about some myself.  I could always use more references though, and maybe you have some I’ve missed.  I’d appreciate an email heh heh.
     
    And lastly, yes that’s the important thing for us.  If only it were the important thing for all.

  31. admin says

    To reiterate, I’m not saying I don’t think point selection matters.  It certainly seems to in my experience.

    What I am saying is that current research doesn’t support the idea that it matters.

    There is a series of German studies that were very well designed that compared a no treatment group with a sham (minimal acupuncture) and active (traditional acupuncture) group.  In four out of five of the studies, both sham and active acupuncture produced greater pain relief than no treatment, but active acupuncture didn’t outperform sham.  (If you’d like the references for these, let me know).

    In the end the important thing is that patients are getting better with almost no risk and side effects.

  32. says

    “I don’t entirely agree that it’s not possible to do good research on the effectiveness of acupuncture” I never meant to say that.  I just said that I don’t think that double blind studies are the best way to do it.
    “What probably has a greater effect on outcomes than the practitioner’s skill or point selection is the meaning that the patient attributes to the treatment. ”
    -respectfully slightly disagree.  I’ve had long time patients where, I admit, sometimes my diagnosis was wrong, my point selection didn’t work.  But when I realized my error and corrected my manipulation and/or points used and that achieved the desired effect.  These are patients that I have seen several times over the years and return for new problems.  Hence, they already have confidence in me and in the medicine.  Yet if you do the wrong thing it doesn’t work…  Hardly ascribable to placebo effect.

  33. says

    I am aware that the WHO has separate guidelines for acupuncture research – I cannot bring up the info off the top of my head but I now have fodder for future blog posts.
    Suffice it to say that I have previously written on one misconception about acupuncture that makes it difficult to formulate studies on it .  In summary it can be stated that “Acupuncture is a procedure, not a pill.”  It is practitioner dependent. There is no one set of “points” for every named western condition.  A practitioner has to determine the root cause behind the given symptoms.
     
    For example both “heat” and “cold” can cause similar respiratory symptoms.  It takes skill both in history taking and physical exam to distinguish between them.  This, plus taking into account the patient’s constitution, occupation, living conditions and diet, may lead a practitioner to prescribe seemingly totally different treatments for what appears to be the same condition.  On the other hand, the same “root” may manifest differently in different people.  Sudden fits of anger may manifest as vertigo in one patient, liver attacking the spleen/stomach and leading to indigestion in another.  In that way, different conditions may appear to be getting similar treatments.
     
    I hope this gives an idea on how difficult it is to do double blind studies.

    • admin says

      Philip,

      I don’t entirely agree that it’s not possible to do good research on the effectiveness of acupuncture. The variation of practitioner skill and point selection can be addressed, at least to some extent, in a well-designed study.

      I know of several studies that have compared various methods of point selection. For example, such a study may have three groups: an untreated control, a “sham” group (with non-penetrating needles like the Streitenberg needle) and a “traditional acupuncture” (TCA) group. The sham group gets skin stimulation at non-acupoints. The TCA group gets regular acupuncture at points selected based on the patient’s disease condition and constitution, and any other appropriate diagnostic methods (i.e. tongue and pulse).

      I’m not sure how much you follow the literature, but there are a surprising number of studies that compare traditional point selection methods including a full diagnosis with “cookbook” acupuncture (i.e. using the same points for each patient). Unfortunately for acupuncturists, these studies don’t demonstrate that point selection makes a difference in patient outcomes.

      Note that I’m not saying point selection doesn’t make a difference. I’m saying the studies done so far don’t demonstrate that it makes a difference in outcomes.

      I’ve seen studies that have used three different acupuncturists, all with more than ten years of training, to administer traditional treatments. Many researchers working in this field are aware that Chinese medicine diagnosis and treatment is individualized, so the more recent studies usually incorporate it.

      What probably has a greater effect on outcomes than the practitioner’s skill or point selection is the meaning that the patient attributes to the treatment. This can be influenced by the practitioner’s manner, the patient’s attitude about the treatment and hope that it will work, and numerous other factors. The importance of the meaning response (which is usually referred to as placebo effect) can’t be underestimated, and as practitioners we ignore it at our own peril.

  34. admin says

    Donna,

    I agree that the lens we look through and the way we define health and disease will affect both the design and outcomes of clinical research.

    However, I don’t agree that current research methods aren’t useful for evaluating the effectiveness of Chinese medicine for particular outcomes.

    We consider the role of the whole body when we examine and treat a patient, but if we fail to address their chief complaint, we’re not doing our job.  That’s why a study that examines the effect of acupuncture on elbow pain is still useful in determining whether acupuncture can relieve elbow pain, provided the study is designed correctly (which all too often it isn’t).

    Acupuncturists would point out that there are a multitude of factors influencing whether a person’s elbow pain improves above and beyond the acupuncture treatment.  But that’s just as true in a study examining whether a drug works for elbow pain, and assuming the sample is properly randomized and the study is properly powered, the effect of this kind of variation should be minimized.

    What is the research methodology you propose for evaluating Chinese medicine? How would it differ from current methodology?

  35. Jesse says

    I would like to thank everyone for your willingness to discuss things with me. I have encountered many ideas in this series for the first time, and am sorta working out what I think of everything as I go. So thanks for your patience.
     
    Philip,
    I’m glad to hear that Chinese medicine is based on science too. In that case it should eventually be accepted into the mainstream, I believe.
    It’s true there is some corruption in science, but I think most of it is eventually worked out through peer review and replication. After all, scientists aren’t paid to question the work of their colleagues, but they do it anyway :)
    I agree that reconciling terminology should help. Defining concepts precisely in ways everyone understands leads to clearer discussions.
     
    Donna,
    Defining what a healthy human being is seems like a good idea. How does one go about doing that?
    You also say chinese medicine should be scrutinized a different way. What sort of research methodology might work for the purpose?

  36. Donna Chang says

    Jesse, one of my teachers have said, ‘When we examine any system of human medicine, we must first ask the question: “According to this medicine, what is a human being?” and, therefore, “What is a healthy human being?”‘ (Liu Ming)
    As Chris said very well in the Part VI article, western medicine mainly geared towards suppressing symptoms. This is the basis of how most researches are designed. For example, there are many clinical trials that follow the same logic: i.e. In a clinical trial, ___% of patients with (_____symptom) who undergo (______treatment, can be a drug, or surgery etc.) show improvement of symptom  compare to ___% who took placebo, compare to the control group…. The basic premise of most clinical trials of this kind is to see statistically how certain symptom is managed with a drug. However, are we just a statistical number? These research methodologies also play down the human factor to try to be “objective” about the results. However, we have to ask, between the drug and the symptom, where is the human being in it? 
    What does that say about the philosophy of western medicine? 
    Chris, I agree with you that chinese medicine has to be subject to scrutiny. But, as you know, Chinese medicine address the whole person, it considers the full range of human experiences (e.g. emotions, lifestyle, diet, climate and other environment factors) that leads to a systemic malfunction/imbalance to that leads to the symptoms. This paradigm is different from western medicine and so chinese medicine should be scrutinized under a different set of research methodology. 
    Philip, 
    well said. as they say, “The difference between a medicinal and a poison is dosing.”

  37. admin says

    Philip,

    I’m going to leave those posts to you!  It’s time for me to move on to other topics. Thanks again for your participation in this series!  I’ve enjoyed our dialogue a lot.

  38. admin says

    Donna,

    I couldn’t agree more with your point, and that’s why I have a blog that challenges mainstream myths on nutrition and health.  But as Philip pointed out, it’s important to subject Chinese medicine to the same scrutiny.  Otherwise we’re just as guilty of what Ratcliffe is referring to.

  39. says

    Jesse: Thank you for your open-mindedness.  I agree with almost everything you said.  Here are the exceptions:
    Yes, western medicine in theory (thank you for pointing that out) is based on science.  However, I would like to point out that so is Chinese medicine.  It is based on evidence – collective experience by practitioners accumulated over millenia – which I’m sure was subjected to the basic rigors of the so-called “scientific method”.  Namely – identify the problem, search for past attempts to solve the problem in the literature, formulate a hypothesis, experiment to prove or disprove the hypothesis, and draw conclusions.  Time has proven that some formulas or point combinations have faded away to obscurity because they don’t work as well as others.
    Secondly, science is only now validating what was known before.  I could fill this comment box with citation after citation concerning the effects of individual chinese herbs – both beneficial and otherwise.  It is difficult to analyze individual components of formulas, but formulas have been studied.  I just gave a lecture last week on scientific studies involving Liu Wei DiHuang Wan (Six Flavor Rehmannia Decoction) where it’s anti diabetic and immune modulating activity is proven through published studies.
    Thank you also for acknowledging that ALL science and ALL medicine have problems.  True, even chinese medicine is the victim of commercialization and money-making chicanery.  I’ve seen patients get kidney failure from overdosing on korean red ginseng, for example.  This was promoted by unscrupulous traders as a panacea… and being “natural” it supposedly had no side effects – forgetting the fact that a very “hot” herb like red ginseng should be used sparingly in a hot humid climate like in my Philippines.
    Donna is correct in that many people trust “scientists” implicitly because we are taught that science is an objective search for truth.  The truth is that modern science is an objective search for funding.
    Chris – I think one of the main problems with reconciling TCM and mainstream western medicine is the seeming inability to reconcile terminology.  It is my adamant belief that TCM will be easier to understand if the TCM philosophy and terminology is explained using the western paradigms – you got the ball rolling with your posts on the meridians.  Are you planning any more?  For example, we know fire = inflammation, what about damp?  or cold? =)

  40. Donna Chang says

    Most of us have been taught that western medicine is based on science, and science represents the unbiased, objective way to search for truth. However, subjective judgments lie behind all the facets of “scientific” research. (Not to mention that nowadays, most clinical research are funded by pharmaceutical companies) 
    All data are theory-, method-, and measurement-dependent. That is, “facts” are determined by the theories and methods that generate their collection; indeed, theories and methods create the facts. 
    This means that how the problem will be defined, which model(s) of inquiry will be considered to be relevant to the problem as defined, which model(s) of inquiry will be considered to be relevant to the problem as defined, where one shall look (and, by implication where on shall not look) for evidence–and even what one shall consider to be constitutive of evidence–are all determined by the paradigmatic “map” or world view to which the scientist is committed. 
    –John Ratcliffe, Notions of validity in qualitative research methodology

  41. Jesse says

    On one level I agree, Philip. Doctors can be wrong: their information can be outdated, and their understanding can be a misinterpretation. It is often good to get more than one opinion on an issue of diagnosis/treatment and try to find a consensus.
     
    On another level, I think “western” medicine is based on science, at least in theory (perhaps not in practice, with every doctor), and I believe the scientific method is a great way to avoid human error. It is not without problems of its own, of course, so here too there is value in seeking a consensus of people who have made a career of looking at the evidence. A few may be fooled by false conclusions, but it seems like the truth should be found by the majority. So it doesn’t surprise me much that people who cannot investigate matters well on their own should put their trust in the mainstream. Does that make sense?

  42. says

    In life there are several ways to enter into belief.  One is through personal experience.  One is through gathering evidence and trying to fit the pieces together, like what we’re trying to do now.  Another is faith.  It’s too bad that there’s no level playing field when it comes to faith in medicine.  Because “western” medicine apparently predominates, “they” say something and people are more than likely to readily believe.  With Chinese medicine, from the point of view of an outsider, we usually demand a bit more, like what we’re doing now.  There’s a double standard though – people are more likely to accept western medicine “pronouncements” on faith alone (faith in medical authority).

  43. says

    Oh, ok. I’ve learned some about the immune system, but it has mostly been in relation to its interaction with pathogens. It seems like my limited knowledge is getting in the way of my understanding more than ignorance would :)

  44. admin says

    Yes, Philip.  The literature suggests that response to needling-induced tissue damage involves Th1 (cell-mediated) immunity, whereas the response to a vaccination involves Th2 (humoral) immunity.

  45. says

    Acupuncture creates an inflammatory response – so the immune cells at work would be macrophages.  Vaccines work by forcing T-cells to go to work.  (If I recall my second year pathology right)

  46. says

    Oh, it would be silly to use vaccines to stimulate the nervous system. I was just wondering whether vaccines might incidentally have the same effect as the acupuncture needles, if they both stimulate the immune system.

    • admin says

      The mechanisms of acupuncture are similar in some regards to vaccination, but very different in other regards. I don’t think they can be considered in the same category.

  47. admin says

    Hypodermic needles are not retained for any significant length of time.  Getting vaccine injections just to stimulate a peripheral nervous system response is certainly overkill. Not to mention the side effects and risks of injecting a modified live virus into the body, which are well documented.

  48. says

    Okay. So, if stimulating the immune system with a needle leads to healing throughout the body, something like vaccines should be even better for that, right? Or any kind of injection, to some extent.

  49. says

    It’s not exactly damage… it’s more of a controlled stimulation.  Pomeranz’s studies show that it is the A-delta fibers which are stimulated and give off the “qi” sensation.  Naloxone blocks this effect and blocks the pain control.

  50. says

    Ok, so it’s the type of damage which elicits a certain pain response that induces painkiller release, rather than the amount of the certain type of pain or something? I get it.

  51. admin says

    Question for you: why do you suspect that longer-term pain relief is due to placebo?  What leads you to that conclusion?
    My answers to your questions:
    1) Unfortunately the reference I have for that is Donald Kendall’s book, and a 8-hour seminar I did with him last weekend.  The information about involvement of proprioceptive fibers in the needling response came from a lecture by Robert Doane, who is an acupuncturist and also a member of the American Academy of Pain Management.  Some of this work hasn’t been published yet, as far as I know, but let me try to explain further.
    My understanding is that propagated sensations induced by afferent nocioceptive fibers triggered by needling are mediated by afferent proprioceptive fibers and propriospinal neural reflexes.  Nocioceptive fibers activate propriospinal fibers to produce muscle flexion responses.  Proprioceptive group II afferents send terminal branches to all laminae except II, and ultimately synapse on motor fibers.  Propriospinal short and long fibers traverse the length of the DLF.
    Somatic and visceral nocioceptive fibers and proprioceptive fibers trigger dorsal root potentials and reflexes (DRR).  These reflect up and down the DLF, firing nerves above and below entry level signal.  These nerves may have a role mediating afferent inputs and supraspinal descending control (which I discussed in the article).
    2) Mast cells do release histamines, and leukotrienes can have inflammatory and anti-inflammatory effects.  What I didn’t make clear in this article due to length considerations is that tissue reactions to needling-induced micro-trauma follow a set order.  The initial response is to mount a strong defensive (inflammatory) reaction.  This is important to keep blood clots from forming so immune cells can flow in.  But all needling induced inflammatory reactants are neutralized in the final phase.
    Vasodilatory, nocioceptive nerve excitation and chemotactic, solubility activities predominate during the initial phases of needling response.  Tissue repair and inactivation of reactants predominate during intermediate and latter phases of reaction.
    3) I am not sure of the exact mechanism, but many studies show that muscular ischemia is a defining characteristic of chronic pain.  Maintenance of sympathetic vasoconstriction of peripheral tissues over time results in ischemia, inflammation and pain.  See this paper for more info.
    I’ve often heard the claim that “little is known about the analgesic effects of acupuncture.” On the contrary, according to Professor Bruce Pomeranz of the University of Toronoto, “We know more about acupuncture analgesia than about many chemical drugs in routine use. For example, we know very little about the mechanisms of most anesthetic gases, but still use them regularly.” (There are of course countless drugs and entire classes of drugs we don’t understand the mechanisms of action for, including aspirin.)
    Moffet’s recent review in the Journal of Clinical Epidemiology demonstrates that acupuncture is distinguishable from placebo and affects outcomes. What is less clear in the literature is whether point selection and technique make a difference in outcomes.

  52. Andrew C says

    Hello, I am skeptical of acupuncture (and homeopathy, and chiropractic, and most other alternative medicine), but would like to ask a few questions so I can at least understand it better – even if I still may not accept its validity! I do recognize its benefit in short-term pain relief through gate control, but suspect longer-term pain relief is due to placebo instead of physiological changes.
    First, do you have a reference for the role of proprioceptors in pain perception? My understanding is that proprioceptors act to inform us of our body position, not pain perception. Pain position is reported by the same nerves as report the pain itself.
    Don’t mast cells also release histamines, which trigger an inflammatory response? According to your description of action (and according to Wikipedia http://en.wikipedia.org/wiki/Inflammation) leukotrienes are also an inflammatory agent, not an anti-inflammatory.
    You say that the body has a long-term response to injury of reducing blood flow to the area. It was my understanding that the vasoconstriction in response to injury was very short-term, around ten minutes, followed by vasodilation.Is there another mechanism for longer-term vasoconstriction to a wound? The texts I have available don’t mention one, but they are rather introductory.
    I apologize if your references address any of these – I’m a broke college student, so don’t want to spend money on more books!

  53. admin says

    Hi Jesse,

    The mechanism is as I described it in the article.  Any penetration of the skin, whether it is perceived as painful for not, will trigger the body’s defense mechanism and stimulate the PNS.  This leads to the cascade of analgesic and anti-inflammatory responses I described.

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