Relationship of γ-aminobutyric acid (GABA) to antianxiety effects of benzodiazepines

Abstract

The role of γ-aminobutyric acid (GABA) in the actions of ben-zodiazepines is considered from a behavioral pharmacology perspective. Much research indicates that GABA mediates various electrophysiological and biochemical actions of benzodiazepines, but the evidence collected to date concerning behavioral actions is mixed. Studies with GABA antagonists support the concept that GABA is important; that is, picrotoxin and bicuculline have been reported to block the behavioral effects of benzodiazepines, although there are some conflicting results. Attempts to demonstrate that GABA agonists can exert benzodiazepine-like behavioral effects have been less successful. Most available studies indicate that muscimol, for example, does not affect various types of suppressed responding, e.g., conflict behavior, as benzodiazepines do. Several lines of evidence suggest that the benzodiazepine receptor in brain is related to the antianxiety actions of benzodiazepines, including a high correlation between potency in the binding assay and potency in the conflict test. Evidence continues to support the hypothesis that the behavioral actions of the benzodiazepines are mediated by serotonin, possibly with the involvement of GABA.