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PARKINSON'S DISEASE, which afflicts over a million Americans, could once be relieved only by severing certain nerve pathways deep in the cerebrum. While the operation relieved the tremors and rigidity of the disease, patients could suffer partial paralysis and loss of speech. Now, most Parkinson's victims can be relieved by a drug known as levodihydroxyphenylalanine, or L-dopa. First used successfully by George Cotzias of the Brookhaven National Laboratory, L-dopa provides a classic example of molecular chemistry at work. Normal movement depends in large part upon the action of dopamine, one of the brain's most important chemical transmitters. Parkinson's disease results from a degeneration of the cells that help produce this chemical. By boosting the level of dopamine in the brain, L-dopa helps to prevent the palsy associated with the disease.
The drug is also enabling doctors to take some tentative yet encouraging steps toward treating Huntington's chorea, a genetically-determined degenerative nerve disease that strikes its vic tims at about the age of 40 and kills them within 15 years. A group headed by Dr. Leslie Iverson, 36, of the British Medical Research Council's Division of Neurochemical Pharmacology, has been studying the chemical changes in brains of Huntington's victims. The team has found that victims of the disease have lower-than-normal quantities of the transmitter gamma amino butyric acid (GABA) and occasionally-elevated amounts of dopamine. They are now trying to develop drugs that will restore the balance between these chemicals.
EPILEPSY, which affects one person out of every 100 is caused by clusters of brain cells, or foci, that discharge electrical impulses paroxysmally. It produces violent seizures resulting in convulsions and unconsciousness, brief staring spells or episodes of uncontrollable rage. Researchers have discovered that most epileptic conditions can be controlled by a drug called Dilantin, which Dr. Frank Morrell, 47, of Chicago's Rush Medical College, believes prevents epileptic discharges from spreading to neighboring neurons.
A technique for relieving cases of epilepsy that resist treatment by drugs has been devised by Dr. Irving Cooper, 51, of St. Barnabas Hospital in New York. Cooper has found that stimulating the cerebellum electrically apparently increases its inhibitory action on the cerebrum. Cooper has implanted electronic "pacemakers" upon the cerebellums of several epileptics, as well as patients suffering from stroke-caused paralysis, cerebral palsy and from dystonia, a neuromuscular defect in which permanently flexed muscles twist and distort the limbs. The device, which stimulates the cerebellum with low-voltage jolts, has produced relief in most of the 70 cases in which it has been used. One muscular 26-year-old man suffered from daily epileptic seizures before he came to Cooper for a pacemaker. Since the machine was implanted a year ago, the man has been free of major seizures.
There are other areas in which neuroscientific research is paying dividends: