Pain of incredible proportions overwhelms all other symptoms and becomes the problem. People so afflicted often cannot work. Their appetite falls off. Physical activity of any kind is exhausting and may aggravate the pain. Soon the person becomes the victim of a vicious circle in which total preoccupation with pain leads to irritability and depression. The sufferer can't sleep at night and the next day's weariness compounds the problem-leading to more irritability, depression, and pain. Specialists call that unhappy state the "terrible triad" of suffering, sleeplessness, and sadness, a calamity that is as hard on the family as it is on the victim. The urge to do something-anything-to stop the pain makes some patients drug dependent and drives others to undergo repeated operations or resort to questionable practitioners who promise quick and permanent "cures."Many chronic pain conditions affect older adults. Arthritis, cancer, and angina commonly take their greatest toll among the middle-aged and elderly. Trigeminal neuralgia (tic douloureux) is a recurrent, stabbing facial pain that is rare among young adults. But ask anyone living in a community for retired persons if there are any trigeminal neuralgia sufferers around and you are sure to hear of cases. So the fact that Americans are living longer contributes to a widespread and growing concern about pain.
Neuroscientists share that concern. At a time when people are living longer and painful conditions abound, the scientists who study the brain have made landmark discoveries that are leading to a better understanding of pain and more effective treatments.
In the past several decades, important discoveries about pain-suppressing chemicals came about because scientists were curious about how morphine and other opium-derived painkillers, or analgesics, work. For some time neuroscientists had known that chemicals were important in conducting nerve signals (small bursts of electric current) from cell to cell. In order for the signal from one cell to reach the next in line, the first cell secretes a chemical, called a "neurotransmitter," from the tip of a long fiber that extends from the cell body. The transmitter molecules cross the gap separating the two cells and attach to special receptor sites on the neighboring cell surface. Some neurotransmitters excite the second cell—allowing it to generate an electrical signal. Others inhibit the second cell—preventing it from generating a signal.
Numerous studies around the world led to the discovery of not just one pain-suppressing chemical in the brain, but a whole family of such proteins. The term "endorphins" is now often used to describe the group as a whole. The discovery of the endorphins lent weight to an overarching theory of pain: endorphins released from brain nerve cells might inhibit spinal cord pain cells through pathways descending from the brain to the spinal cord.
Further evidence that endorphins figure importantly in pain control came from studies of some of the oldest and newest pain treatments. These studies involved the use of a drug called naloxone that prevents endorphins and morphine from working.
.jpg)
