Do pain receptors exist?

In 1996 a physicist Alan Sokal submitted a nonsensical research paper filled with jargon to the Social Text, a journal published by Duke. His goal was to prove that the many journals of the day were nothing more than “…fawning references, grandiose quotations, and outright nonsense.” In other words…politically correct pseudoscience. His paper was published and almost simultaneously Sokal came out in several other papers pointing to his hoax and making fools of the editors.

Not always the goal of the hoaxes is so noble. Most of the time they are schemes intended to make the schemers very rich in the account of the fooled audience.
Around 1970 Manuel Elizalde, Prime Minister of the Philippines came forth to the world claiming that he had discovered a Stone Age tribe called the Tasaday on the island of Mindano. When scientists tried to get a closer look, however, he declared the island to be an off-limits land reserve. After being deposed about 15 years later, several journalists finally visited the island only to find the Tasaday walking around in blue jeans and speaking a modern dialect. They explained that they had moved into caves under pressure from the minister. Elizalde, however, was long gone as he had already fled the country with millions of dollars from an account set up to help protect the Tasaday people.

The big question is why people are so susceptible to such hoaxes even in this day of age when everybody is comparatively educated. The problem is that despite massage schools giving hands-on practitioners sufficient theoretical foundation it cannot teach them so called modern science. The disparity between the modern science and the average clinician nowadays is probably greater than perhaps it was centuries ago. Science became so specialized that unless you are a part of the one particular branch, it’s really above your head. Besides, massage therapist whose main occupation is clinical work don’t really have to study scientific papers not related to their hands-on performances. In any case, since one has no choice but to trust scientists who are on the cutting edge of research and development, they must have high integrity and provide good and trustworthy information.

However, what if they don’t? How can average clinician separate truth from a sophisticated, scientifically sounded lie or simply research of a very poor quality? Incidentally, during the last 20 years 50% of scientific data cannot be produced. I cannot recall it being this way before.

no_spiralIt is said that all new is well forgotten old. Actually, the proverb is somewhat vague.This “new” isn’t exactly the same as the forgotten old, but a similar to a position on a spiral that is exactly above the old knowledge. In other words it doesn’t negate the knowledge that is directly behind it, but builds on it and expands its boundaries for new situations and different cases.

For example Einstein Theory of Relativity didn’t cancel out Newton’s laws, but only expanded and corrected them in the range of very high velocities.

So if we see that the “new” theory out right cancels all the old knowledge, this is a first indication that we need to be careful because it is probably a hoax.

This warning is often forgotten by overzealous proponent of “new.” Over the course of my career not once I observed these trends sparking in the massage community consciousness, do some wavering and then extinguish.

Lately such drift arose over sensation of pain. In general, pain is a complex phenomenon. It could be caused by many different sources. Yet the tendency I am about to discuss dismisses the existence of pain receptors and narrows down its source to brain only. The following are the postulates of this “new” trend, packaged as “four things that every therapist should know.”

  1. There is no such thing as a pain receptor
  2. The brain does not receive pain signals
  3. Pain is created by the brain as a protective response to perceived threat.
  4. Pain science is a sub-discipline of neuroscience that has its own peer-reviewed journal(s), its own international association and conferences, and a massive amount of ongoing research and clinical work being done.

At the heart of these quite nontrivial conclusions lay, as I was informed, the Neuromatrix theory of Professor Melzack.
It would be safe to say that I was familiar with Prof. Melzack ‘s works, including Neuromatrix theory and by no means couldn’t find that in his works he is suggesting There is no such thing as a pain receptor.

However, let’s examine those claims closer.

Prof.Melzack defines neuromatrix/mechanism as

NETWORK OF NEURONES WHICH CREATED “ LOOPS” OF “PAIN MEMORY” INSIDE THE CORTEX AND HYPOTHALAMUS. WITH TIME THESE LOOPS ABLE TO GENERATE PAIN INDEPENDENTLY AND CONTRIBUTE TO FORMATION OF PAIN SENSATION.
But such network of neurons is not limited to pain sensation only

Nociception can also cause generalized autonomic responses before or without reaching consciousness to cause pallor, diaphoresis, tachycardia, hypertension, lightheadedness, nausea and fainting.[6] as you can see it is a very complicated physiology and pathophysiology. In such a case we are talking about brain generating painful emotional memories/ neuromatrix. In most cases we are dealing with tissue injuries type of pain, that can initiate development of neuromatrix, in both cases massage therapy is powerful.

Having a high respect for Professor Melzack’s works I decided to reread his work and spent some extra time studying it. Therefore right now I’d like to re-examine those snippets of his Neuromatrix theory that lead the self-proclaimed massage-scientists to the discovery of having no pain receptors.

It was once popular to identify one of these types as the specific ‘pain receptors’. We now believe that receptor mechanisms are more complicated. There is general agreement that the receptors which respond to noxious stimulation are widely branching, bushy networks of fibres that penetrate the layers of the skin in such a way that their receptive fields overlap extensively with one another. “

Is Prof. Melzack denying the existence of pain receptors? He is just stating his opinion that ”receptor mechanisms are more complicated” that it was thought of before.

Thus damage at any point on the skin will activate at least two or more of these networks and initiate the transmission of trains of nerve impulses along sensory nerve fibres that run from the finger into the spinal cord.

Again what kind of impulse would transmit pain, if not a pain impulse? Would such an impulse be transmitting touch sensation, pressure sensation, etc? Of course not, because when one burns the finger, he or she is experiencing pain. How else can it be called other than pain receptors, or nociceptors?

Nociceptors, additionally to other sensations mainly reporting pain, and therefore in most literature it is given both definitions: nociceptors or pain receptors.

What enters the spinal cord of the central nervous system is a coded pattern of nerve impulses, travelling along many fibres and moving at different speeds and with different frequencies…”

Going back to the same example, when you burn your finger what kind of impulse will it be if not pain impulse, that reaches the brain?

In the end, examining these snippets that were offered me as unarguable proof of non-existence of pain receptors; I can only conclude that someone really tried to interpret Melzack’s words like that. The work itself contains none of that.


The brain does not receive pain signals


Pain is created by the brain as a protective response to perceived threat.

Why should I care? Rather why should we as a massage community care that some of our colleagues promote this claim? Well because it becomes a massive phenomenon. Many massage therapists adopt this claim. More than this, learning from external to massage therapy sources how to treat patients by teaching them that all pains are generated by brain.


Dear client, you’ve injured your knee or other body part, or suffer from a painful spinal and joints degenerative diseases… Fear not. All your pain is in your head.

Instead of addressing the causes that produce pains by means of massage, a massage therapist is beginning to practice clinical psychology.
I hope we all agree, that the mind is fragile, and some of our clients can indeed sustain painful psychological trauma, if we are to teach them this kind of stuff.
Besides we are massage therapists, and mainly should work with our hands. Of course it is good idea to be able to briefly explain our clients the physiological effect of massage what tissue injuries pain is, as well as that there is such a thing as memory pain. Both these cases covered in my article The impact of Neuromatrix on the “Body Cells Carry Emotional Memory” theory and its implication in massage
In both cases massage therapy can play a crucial role.

In both cases massage therapy can play a crucial role.

The second reason for us to be worrying with this claim is that this claims denying centuries build understanding of medical physiology, as well as other biomedical science
As I explained above, in general spiral is how science develops. For example pain receptors where discovered in the 19 century. This scientific data was reproduced probably 1000 times. Using these knowledge as foundation many other discoveries where made. New discoveries and new data would always be found. In no case they would deny the entire existing body of knowledge, medical physiology, pathology, etc.

The main argument of the proponents of “pain receptors don’t exist” claim is that nociceptors is not a pain receptor.

 

Let’s see how the Dorland’s Medical Dictionary for Health Consumers would define a nociceptor?

Nociceptor /no·ci·cep·tor/ (-sep´ter) a receptor for pain caused by injury, physical or chemical, to body tissues. nocicep´tive

 

Dorland’s Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

 

So it looks to me that it is in fact a pain receptor if the main piece of information that it reports is pain.

 

What follows is that if nociceptors report to brain, then brain receives impulses. Additionally to pain nociceptors, report cold and hot sensations.

 

Take a big piece of ice, and place it against skin. Nociceptors will report cold sensation. Then press it hard enough against skin. The same nociceptor would report pain.

 

In another scenario keep ice against the skin. In the beginning nociceptors will report cold then continue to keep it for a long time, and the same receptors / nociceptors would report pain.
Now, if you google for “pain receptors”, most likely, you find many different definitions that would equate pain receptors with nociceptors. Sometimes, in the same presentation you could find both definitions. In medical literature in the same text, you would see definitions of pain receptors and nociceptors interchangeable because mainly nociceptors reporting pain.
The other claim is,that noxious stimulus, is generated by brain only.

From Wikipedia, the free encyclopedia:


A noxious stimulus is “an actually or potentially tissue damaging event.” It is a prerequisite for nociception, which itself is a prerequisite for nociceptive pain.[1]
Noxious stimuli can either be mechanical (e.g. pinching or other tissue deformation), chemical (e.g. exposure to acid or irritant), or thermal (e.g. high or low temperatures).

There are some types of tissue damage that are not detected by any sensory receptors, and thus cannot cause pain. Therefore, not all noxious stimuli are adequate stimuli of nociceptors. The adequate stimuli of nociceptors are termed nociceptive stimuli.


A nociceptive stimulus is defined as” an actually or potentially tissue damaging event transduced and encoded by nociceptors.

If one was to take a sharp knife, and place it against the skin applying a moderate pressure, most likely, one wouldn’t experience this neither as sensation of pressure nor as sensation of pain. This is so called noxious stimulus; potentially damaging for tissue event transduced and encoded by nociceptors.

Yet if one continues to press hard or even damages the skin then, surely, this one would experience pain.

Can our community afford the spread this type of disinformation?


The impact of adopting “pain receptor doesn’t exist” view on the massage community

What does it mean one concept of multidisciplinary approach to pain management? Physical therapists, chiropractors, clinical psychologists, MDs and we each contribute their technical approaches to improve health of patients. These are different scopes of practice.

Physical therapists, chiropractors, clinical psychologists, MDs, would appreciate you buying their books, attending seminars etc., However, the moment you will try to cross lines of scope of their practice it would give them an excuse to take over our industry.

Here in California we used to practice under adult entertainment licenses. When two trade associations, including not members of those associations, all united to get the state certifications, guess who our main opposition was?

Thank God, and thanks to very hard work of our people, we got it. We got it, however, under strict condition of physical therapists and chiropractors, of not crossing scope of practice even for a tincture. OR ELSE…………………

That’s why when massage therapists started calling themselves manual therapists, Physical Therapy Association was ready to take us under their control.

As for me…I don’t see the point in crossing the scope of practice line in order to achieve good and sustained results.  Massage therapy is powerful enough.  We are first door providers, and can survive well. However in all cases, the only condition to succeed, no matter where you practice, being it in your office, or in integrative medicine settings, in spas, massage centers, doing house calls, etc., you must be capable to deliver results.

I strongly believe in integrative approach in treatments.  Personally, I work with many chiropractors, physical therapists, MDs, but always remember that I am practicing medical massage, and contributing my best to improve patients’ health conditions without crossing the lines of scope of practice.

This is what any healthcare is all about; to achieve results with minimum or no side effects. From this perspective we guys in a very good place.

Now let’s come back to the idea of why would anybody need to create such a diversion and who benefits from it?  The best analysis angle here is: follow the money trail.

Definitely people who push this.  They would get great monetary benefits by selling their books and imposing programs in massage schools and continued education courses.

Where would it lead massage industry?  To the path to the destruction.

  1. If clients wouldn’t get a real treatment, less and less they would think of massage therapist as a specialist who can alleviate their aches and pains.
  2. Massage would be downgraded to the “feel good” experience where it once was standing right next to adult entertainment industry.
  3. Worst of all the great and powerful skills would be lost and good massage therapist would infiltrate the endangered species list.
  4. As a result lost of massage therapists would lose their clients base.  This once powerful profession would deteriorate.

And who would answer for it?  Definitely not those who caused all the commotion.  Like Elizalde, they would be long gone to some tropical islands with millions of dollars, leaving many massage therapists without work and many suffering people without help.

2 thoughts on “Do pain receptors exist?”

  1. Pingback: The impact of Neuromatrix on the “Body Cells Carry Emotional Memory” theory and its implication in massage. | Medical Massage

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