Freedom From Pain(Physiology Of Pain)

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Vedanta Kesary, 1992 March, p.82-9

In ancient times chronic pain was attributed to evil influences. Egyptians of those early days believed that it was caused by angry gods and spirits of the dead, and the only way of overcoming it was to propitiate these beings of the subtle worlds. By the 16th century BC, however, they discovered that pain could be dealt with by opium. It was thought that the physical locus of pain was the heart. But much of the material related to the physiological aspect of pain is paraphrased in this essay from Claudia Wallis's highly informative article 'Unlocking Pain's Secrets,' TIME (June 11, 1984).

Greek philosophers, notably Democritus and Plato, came to the conclusion that it was not the heart but the brain that 'perceived' pain. This was a right conclusion, but the details remained more or less unknown.

Pain-research in the last two or three decades has thrown some light on the matter. Briefly this is what happens when, say, the big toe collides with a large, solid object. The pain message originates at the point of contact, beginning with the release of a few potent chemicals that are normally stored in or near all nerve endings. Among these chemicals are Prostaglandins, Bradykinin, and a 'mysterious' substance P (for They sensitize the nerve endings and help transmit the pain message as an electrochemical impulse from the injured region to the dorsal horn of the spinal cord. From there it is relayed as a chemical message to the brain, where the sensation first becomes conscious, and the intensity and location of pain are recognized.

It has also been discovered that only a limited amount of sensory information can be processed by the nervous system at any given moment. When too much information is sent through, certain cells in the spinal column interrupt the signal, as if closing a gate.

This discovery has become known as the gate-control theory of pain and it explains why massaging or patting the sore area gives some relief. This theory serves as the basis for a now widely used analgesic therapy known as Transcutaneous electrical nerve stimulation, or TENS. Electrodes are attached to the skin above a painful area, and a mild current is generated to compete with the pain signal. The stimulation of acupuncture needles is also believed to work, in part, by shutting the pain gate.

The presence of this 'mysterious' substance is a sufficient proof that the domain of pain still remains a largely unexplored territory. The gate-control theory also explains why one may not 'feel' the pain from an obvious physical source so long as one is engrossed in an activity that produces sensations which are more powerful than the pain sensation. One example of this is the soccer player who is often so absorbed in play that he may not notice until the game is over that he has perhaps dislocated a shoulder or has a swollen ankle. Obviously, 'something' in the system was suppressing his pain.

Scientists discovered in 1975 what that 'something' might be. They say that our brain and spinal cord have in them some powerful pain-blocking chemicals called Endomorphins —and these are that 'something' which switches off the pain alarm. Opiate drugs like morphine and heroin also have this capacity to activate the body's pain-relief system. Several types of natural opiates have been identified, along with other non- opiates produced in the body, that can alter the pain message. Some of these not only are associated with pain but are also involved in emotional responses like depression.

Pain-researchers now admit that pain is a complex experience that involves emotions, previous experiences with pain, and what the pain means to us at any given time. It is clear that no one can pinpoint where the physiology of pain ends and the psychology of pain begins.

About The Author

Swami Tyagananda

Swami Tyagananda is a monk of the Ramakrishna Order and presently head of the Ramakrishna Vedanta Society in Boston.