Benzodiazepine binding after in vivo elevation of GABA

[3H]Diazepam binding was measured in rat cortical membranes. Acute and chronic amino-oxyacetic acid (AOAA) pretreatment greatly increased GABA levels, but did not alter diazepam binding. The GABA normally present was sufficient to maximally stimulate diazepam binding. In in vivo binding studies, acute and chronic AOAA treatment increased the amount of [3H]diazepam in the brain at the time of sacrifice, thus increasing both specific and nonspecific binding and leaving unchanged the fraction of drug specifically bound. Fluctuation of brain GABA may not affect benzodiazepine binding unless the normal concentration is greatly depressed.