Effects of tranquillising, antidepressant and central nervous system stimulant drugs on the gamma-aminobutyric acid (GABA) level of rat brain.

The level of y-aminobutyric acid (GABA) was determined in the brain of rats 1 hr. after i.p. injection of chlorpromazine, prochlorperazine, diazepam, trimipramine, methamphetamine and nikethamide. Diazepam increased, and, trimipramine and amphetamine decreased the brain GABA level over wide dose ranges. Low doses of chlorpromazine and prochlorperazine increased but high doses of the drugs reduced the GABA level. Low doses of nikethamide reduced whereas high doses increased the level of GABA. The effects of the drugs have been discussed in relation to the brain GABA level.