Co-operative effect between γ-aminobutyric acid A receptors and central-type benzodiazepine receptors on amylase release in rat parotid acinar cells

We investigated the inhibitory role of γ-aminobutyric acid a (gabaa) receptors on amylase release and the evidence for functional coupling with central-type benzodiazepine receptors in rat parotid acinar cells. muscimol and gaba decreased isoprenaline-induced amylase release. this effect was blocked by bicuculline,a gabaa-receptor antagonist,and enhanced by clonazepam,a central-type benzodiazepine-receptor agonist,and diazepam,a central- and peripheral-type benzodiazepine-receptor agonist. although bicuculline completely blocked the combination effect of gaba a-receptor agonist and clonazepam,it did not completely block the combination effect with diazepam. these results suggest that protein secretion is suppressively regulated by gabaa receptors coupled with central-type benzodiazepine receptors. ©2010 the japanese pharmacological society.