November/December 2001
The Biochemistry and Pleasure and Pain
by Mary Dante


One of the most challenging and most satisfying aspects of S/M play involves dancing along the blurry line that separates pain from pleasure. For the uninitiated, the ability to experience pleasure from a stimulus that should produce intense physical and/or emotional discomfort is unfathomable. But, like most mysteries, knowing how (and why) makes things appear simple.

All sensory input (touch, temperature, sound, vision, taste and pain) enters the nervous system by stimulating specific receptors or specific nerve cells. When a receptor is activated, it causes changes in the membrane of the nerve cell to produce a current similar to an electrical current. This signal can be conducted for long distances in the body, allowing the brain to know what is happening to the fingers, toes, etc. Pain is a sensation produced by the input of a noxious or damaging stimulus that can injure the skin or an organ. It is the nervous system's way of telling the body that it is being damaged unless things change. It's a highly evolved system of body sensation that involves both the lower nervous centers of the spinal cord and the higher centers of the brain. Pain can be seen as either an objective or a subjective experience, due to the complexity and multiple areas of the nervous system involved.

The body has a pain reflex. This response is similar to the kneejerk reflex that happens when the doctor taps your knee with a rubber hammer. When a body part is exposed to something that causes tissue damage, such as extreme heat or a puncture, pain nerves are stimulated. This input goes to the spinal cord and, without any help from the brain, information from the spinal cord goes to the muscles in the affected area, causing that body part to immediately draw closer to the body and away from what caused the pain. Because this is an automatic response, it is objective pain. The body reacts to obvious injury without thinking. Sometimes, however, the body reacts to a stimulus that does not produce an injury but still feels painful. In this response, the nerve cell is stimulated and the input goes first to the spinal cord, then up to the brain. The input is transmitted to the thalamus (a part of the brain that integrates the pain input with other sensory input) and then relays it to other parts of the brain, including the cerebral cortex (the consciousness), the hypothalamus (the unconsciousness), and the limbic system (the id). Because this allows the higher centers of the nervous system to interpret the stimulus, it is subjective pain. The body reacts due to thought, conscious or unconscious.

Some people respond pleasurably to stimuli that others find painful because their higher centers do not interpret the input as pain. When pain input enters the brain, it goes to the hypolhalamus, a region of the brain that controls body functions. These functions include heart and respiratory rate, temperature, hormone release, sexual arousal and genital erection. In some people, the pain input stimulates nerves that provoke sexual responses. These people are sometimes called "hard-wired" masochists. It is unconscious perception of pain as pleasure. On the other hand, some people do not respond reflexively to stimulation which causes tissue damage because they directly and consciously inhibit the body's response to the input. Because pain input enters the cerebral cortex, it enters the realm of consciousness. Individuals who through experience have been able to associate a painful sensation to another sensation that is pleasurable such as the caress of the Master's or Mistress's hand or sexual stimulation can develop connections between the cerebrum and the nerve cells in the spinal cord. Through these connections the cortex can inhibit nerve cells that receive pain input from relaying that information any further. These people often speak of "turning the pain into pleasure," but it is actually the conscious decision to misinterpret pain.

The human body may also unconsciously decide to misinterpret or deny pain. This is accomplished by the release of opioid peptides produced by the body itself. These include enkophatins and endorphins, released by the brain centers that process pain information in response to pain or stress. Because they bind to the same receptors as opiate drugs like morphine, they produce a similar analgesia. They are usually produced in very small quantities, but some people can release enough opioids to cause a "high" or euphoria. During this "endorphin rush," a good Top will take greater care to prevent inadvertent injury to the bottom.

Pain is an extraordinarily important way for the body to gauge its safety and integrity. For safe and sane play, it is of ultimate importance that the body be awake, alert and fully functioning. Only in this manner can both the Top and the bottom insure that the body (and the emotions) respond appropriately to the stimuli applied to the bottom. For this reason, drug and alcohol consumption before and during play should be avoided. Drugs and alcohol affect the transmission and reception of nerve impulses, altering sensation and judgment. This could not only potentially allow play to go beyond what the body can physically take without serious damage, it could also deaden the pleasure derived from play. It is vitally important for Tops to know the physical status of their bottoms. Certain diseases, including diabetes and AIDS, cause spinal nerve pathologies called neuropathies. People with back problems, especially slipped discs, may have compression of spinal cord nerves. In such cases, the nerves may not be able to collectively transmit impulses to the central nervous system, or the injury may cause an over-response to a pain stimulus. Tops playing with these individuals must take extra care to monitor their bottoms for bruising, abrasion, etc., since they may be unable to monitor themselves.

The best, most enjoyable scenes occur when the bottom is physically and mentally healthy, alert and relaxed. The body can then respond to both objective and subjective pain. As any experienced Top knows, it's no more fun to have a tense bottom that overreacts to sensation any more than it is to have one who responds only to injury. But when the two are balanced, the S/M magic occurs, and the exchange between Top and bottom grows greater as they dance together along the edge -- safely.