Abstract: The changes in brain transmitter contents of monoamines and aminoacids were studied with materials of 111 rats poisoned seriously by lithiumchloride. The result showed that when serum lithum level reached 2.67±0.9meq/L., and cerebellum lithium level reached 2.05±0.92meq/kg., DA and GAwere decreased while 5-HT, 5-HIAA and GABA were increased in thewhole brain (decerebellum) of the experimental group. So far as each areaof brain was concerned, DA was decreased, and 5-HIAA was increasedin Telencephalon; NE was decreased and 5-HT was in creased in Dience-phalon; 4 kinds of monoamines did not display obvious changes in the brainstem but GABA was increased in the whole of the three areas of the brain. The results seem to be supportive to the theory of monoamine aboutaffective disorders. It is possible that effect of lithium on brain is to regulatethe dynamic balance between indoleamines and catacholamines, not only tochange a certain single transmitter. This is not the unique and specificmechanism of lithum effect, because it also makes GABA increase in thewhole of the three areas of the brain, including brain stem.

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