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Researchers have puzzled how PD symptoms, due to underactivity in the basal ganglia, and dyskinesia, due to overactivity, can both be reduced at the same time by pallidotomy, where a small bit of tissue in the globus pallidus is destroyed by means of a probe. Nor do they understand how virtually the same effect can result from chronic stimulation of the very same area by a harmless 100-Hz electric signal. Now evidence is growing that drugs which block glutamate, an important neurotransmitter of the basal ganglia, may produce effects like those of pallidotomy or pallidal stimulation, without any surgical intrusion at all.* The particular type of glutamate involved is N-methyl-D-aspartate (NMDA). The NMDA-blocker LY235959 has worked in MPTP monkeys. Some drugs already in clinical use, such as amantadine and memantine, are NMDA-blockers, and that property is suspected to be responsible for their beneficial effect. The search is on for a possible non- surgical alternative to pallidotomy or pallidal stimulation. * Papa S, Chase T; Ann Neur 1996;39:574-578: * Greenamyre T; Ann Neur 1996;39:557-558: Cheers, Joe J. R. Bruman (818) 789-3694 3527 Cody Road Sherman Oaks CA 91403