Benzodiazepines stimulate muscimol receptor binding in an Ro 15-1788 reversible manner.

Diazepam and other benzodiazepines caused a concentration-dependent increase of [3H]muscimol (15 nM) specific binding. The maximal increase was 23.6 +/- 5% at the diazepam concentration of 10 microM. Concentrations of half-maximal stimulation for diazepam and clonazepam were 43 +/- 17 and 12.6 +/- 6 nM respectively. Ro 15-1788 was found to inhibit the stimulation of muscimol specific binding induced by other benzodiazepines. The IC50 for diazepam (1000 nM)-induced stimulation was 280 +/- 60 nM. Intensive treatment of membranes with Triton X-100 decreased the stimulatory effect of benzodiazepines.