Acetylcholine metabolism in rat cerebral cortex after joint and separate administration of gamma-aminobutyric acid and bicuculline.

Bicuculline (BK) administered into the lateral ventricle (i.v.c.) of Wistar rats in a dose of 10 microgram reduced the level and the intensity of acetylcholine (ACh) synthesis in rat brain cortex. On the other hand, Bk administered in the same way in doses of 1, 5 and 10 microgram decreased the activity of acetylcholine esterase. Gamma-aminobutyric acid (GABA) administered i.v.c. in a dose of 600 microgram increased the level and synthesis of ACh and the activity of choline acetyltransferase in rat cortex. The effects of GABA were abolished, however, by pretreatment with Bk.