SCOPOLAMINE-INDUCED CONVULSIONS IN FOOD GIVEN FASTED MICE - EFFECTS OF PHYSOSTIGMINE AND MK-801

We recently reported that scopolamine pretreated mice fasted for 48 h developed clonic convulsions soon after they were allowed to eat a sma ll amount of food for 30 s. The present experiments were performed to determine whether animals also develop convulsions when they were allo wed to eat ad libitum and to find some evidence for the contribution o f the cholinergic and/or glutamatergic systems in the underlying mecha nism(s) of convulsions. Animals fasted for 48 h were treated with 3 mg /kg scopolamine or saline. Twenty minutes later, they were allowed to eat either ad libitum or a small portion of food for 30 s. Scopolamine pretreated animals after starting to eat ad libitum or a small amount in a restricted time developed convulsions in a few minutes, the inci dence being 76 and 54%, respectively. Pretreatment of 0.17 mg/kg MK-80 1, the noncompetitive NMDA antagonist, decreased the incidence of scop olamine-induced convulsions (22%) without affecting latency to the ons et of seizures, Pretreatment of 0.1 mg/kg physostigmine, the cholinest erase inhibitor, changed neither the incidence (90%) nor latency to th e onset of scopolamine-induced convulsions. (C) 1997 Elsevier Science B.V.