Synergic effect of diazepam and muscimol via presynaptic GABAA receptors on glutamatergic evoked EPSCs

► Modulation of diazepam (DZP) and/or muscimol (Mus) at a single excitatory synapse. ► Presynaptic GABAA receptors activation by DZP and Mus induced presynaptic inhibition. ► Co-application of DZP and Mus at low concentrations induced presynaptic inhibition. ► Marked desensitization of inhibition was muscimol at higher concentrations than 10 μM.