MK-801 and dopaminergic system in electrically-induced convulsions in mice.

In this study, the effects of MK-801 and selective dopaminergic agents on electrically-induced convulsions in mice were examined. MK-801 (0.004-0.1 mg/kg, ip) showed significant and dose-dependent anticonvulsive effects, and the anticonvulsive effects of MK-801 (0.02 mg/kg, ip) were not antagonized by dopamine selective antagonists, SCH-23390 (D1, 0.1 mg/kg, sc), sulpiride (D2, 100 mg/kg, sc) and pimozide (D2, 0.5 mg/kg, sc). Apomorphine (0.02-0.5 mg/kg, sc), a D1/D2 agonist, showed proconvulsant effect on electrically-induced convulsions. Dopamine selective antagonists, SCH-23390 (0.02-0.5 mg/kg, sc), sulpiride (5-100 mg/kg, sc) and pimozide (0.1-2.5 mg/kg, ip), also showed proconvulsant effect. However, these effects of dopamine agonist and antagonists were not dose-dependent. These findings suggest that the dopaminergic system neither plays an inhibitory role, at least on electrically-induced convulsions in mice, nor contributes to the anticonvulsant effect of MK-801 in electrically-induced convulsions.