Time course of the effects produced by MPEP on male sexual behavior. MPEP (20 mg/kg, i.p.), when administered 30 min or 60 min, but not 120 min, prior to testing, significantly inhibited sexual behavior as evaluated by mount latency (A) and frequency (B), intromission latency (C) and frequency (D), ejaculation latency (E) and postejaculatory interval (F). *p<0.05, **p<0.01, ***p<0.001, when compared with vehicle treatment group.