Involvement of central cholinoceptors in Metrazol-induced convulsions.

Atropine sulphate (10 mg/kg IP) afforded 90% protection against clonic convulsions induced by standard doses of metrazol (80 mg/kg SC) in mice, whereas atropine methonitrate (10 mg/kg IP) did not offer any protection. Furthermore, physostigmine (1 mg/kg IP) caused recurrence of convulsions in atropinzed metrazol-treated mice and converted the subconvulsive dose of metrazol (40 mg/kg SC) into a 100% convulsive dose. However, neostigmine (1 mg/kg IP) did not antagonize the protection afforded by atropine sulphate against metrazol. The results of the study suggest an involvement of central cholinergic mechanisms in metrazol-induced convulsions.