In mice repeated administration of electroconvulsive shock or desmethylimipramine produces rapid alterations in 5-HT2-mediated head-twitch responses and cortical 5-HT2 receptor number.

Mice treated with a single electroconvulsive shock (ECS) daily for up to 3 days showed progressively enhanced head-twitch to 5-methoxy-N,N'-dimethyltryptamine 24 h after 1,2 and 3 shocks. Injection of desmethylimipramine (DMI, 5 mg/kg) twice daily for up to 3.5 days progressively decreased head-twitch responses on days 2, 3 and 4. Cortical [3H]ketanserin binding was increased by ECS X 3 and decreased by 3.5 days DMI treatment. These data demonstrate that in mice antidepressant treatments produce rapid changes 5-HT2 function.