LEARNING MORE ABOUT PAIN

An hour of pain is as long as a day of pleasure, says the old proverb. For some, those hours turn into days and years of unremitting pain from torn nerves, a blood-starved heart and cancer. Fortunately, medical science has learned much about pain, its causes, and how to stop it.

That knowledge was a godsend to Arlynn Munro of Fullerton, California, who worked as a secretary at Disneyland. Years ago her sciatic nerve - a nerve exiting the spinal cord - was pinched in an injury, sending waves of burning pain into her leg and back.

"I was in such a state, I couldn't stand myself," says Mrs. Munro. "I limped. I could not sleep. I couldn't hold a steady job."

Mrs. Munro found her way to Dr. Ronald Young, chief neurosurgeon for the University of California at Irvine Medical Center. Dr. Young put fine platinum wires into Mrs. Munro's brain, where the wires deliver tiny electric shocks. The surgeon also implanted a tiny battery-powered shock generator in her chest, with wires leading to her brain's pain-control centers. She can turn the generator on and off with a magnet applied to her skin. When she tried turning it off for a week, the pain came back.

"Shortly after surgery, I had relief," says Mrs. Munro. "I now feel a warm, tingling sensation across my lower back and down the left leg. The pain has stopped. It has changed my life."

Dr. Young, one of a limited number of doctors in the country able to do this operation, admits that nobody yet knows exactly why the method works but says that its effect "can be tremendously dramatic." He adds, "Patients had this pain, and now it's miraculously gone." It works for 7 of 10 patients, he says.

Brain stimulation is for those patients who cannot bear their pain anymore. Doctors and scientists also have developed new techniques to relieve a variety of pains. They have new drugs, new devices, and new ways to use old medicines, all of which can eliminate or reduce pain. Here are some of them:

• Injection of opiates including morphine into the spine to block nerve transmission to the brain
• New painkilling compounds
• Electrical shocks to nerves that shut off the pain patterns
• Hypnosis and behavior therapy
• A system that allows patients to inject themselves with painkillers

Scientists now know which nerves carry the pain signals. They understand how injured tissue releases chemicals that trigger those nerves. They know which nerve channels in the spinal cord carry which pain signals, and they have a general idea of the location of the brain's pain detection center.

Scientists also have unraveled part of the mystery of how aspirin works. First they found that the body reacts to injury by making a chemical called prostaglandin. Prostaglandin triggers the nerves that carry pain signals. Aspirin slows prostaglandin's release and thus dulls pain.

Now, in addition to aspirin, there's a whole class of medicines that inhibit prostaglandin. Two of them are sold in over-the-counter drugs: acetaminophen (e.g., Tylenol) and ibuprofen (in both Nuprin and Advil). Stronger doses of ibuprofen can be obtained by prescription. For more powerful prostaglandin inhibitors, you must ask your physician to consider prescribing them.