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Current Science Reviews by Joe Bruman (part 4 of 4) Arendt J; BMJ, 18 May 1996:1242-1243: Melatonin, the hormone of the pineal gland, is strictly controlled by prescription in the UK, but freely available in the USA. consequently it is used by millions of Americans for a large variety of supposed benefits. Melatonin does relieve temporary insomnia or jet lag, and has had numerous trials for other objectives, but claims that it is an antioxidant, immunostimulant, contraceptive, prevents aging, improves cardiovascular and sexual function, or cures AD or AIDS, are premature. Greenamyre J; Ann Neur 1996;39:557-558: A class of drugs called glutamate receptor antagonists interferes with the glutamatergic subthalamic nucleus, whose overactivity projected to the globus pallidus in turn causes symptoms of parkinsonism. Those drugs include amantadine, memantine, and budipine, as well as the experimental drug LY235959 (see part 3). Experimenters found that such antagonists administered either stereotactically or systemically can reduce the amount of levodopa required to control primary symptoms of PD, while at the same time they suppress the levodopa-induced dyskinesia of advanced PD. Thus it appears that drugs may possibly substitute for surgical pallidotomy or pallidal stimulation. Moreover, glutamate antagonists may have a neuroprotective effect that slows progression of PD. Further testing awaits advent of more specific and better-tolerated compounds. Louis E, Ottman R; Neur 1996;46:1200-1205: Etiology and prevalence of essential tremor remain obscure. Estimates range as high as 20 times the prevalence of PD. Some PET studies link ET to increased cerebellar activity. There is inconclusive evidence of genetic susceptibility. Boeker H et al; Ann Neur 1996;39:650-658: Authors used PET scans to assess the geographic effect of ethanol on essential tremor in 6 ET patients and 6 controls. Ethanol reduced blood flow to the cerebellum in all subjects, leading to suppression of tremor in the ET patients. The suppression is mediated via reduction of cerebellar synaptic overactivity which causes increased afferent input to the inferior olivary nuclei. J. R. Bruman (818) 789-3694 3527 Cody Road Sherman Oaks CA 91403