Anticatatonic effect of clonidine: its interaction with dopaminergic, anticholinergic and GABA-ergic drugs

Anticatatonic effects of systemic (50 micrograms/kg, i.p.) and intracerebroventricularly (5 micrograms/10 microliters/rat) administered clonidine was studied in rats against perphenazine-induced catatonia. Clonidine was found to possess anticatatonic actions in rats as it significantly blocked perphenazine-induced catatonia. When clonidine was administered simultaneously with dopaminergic (dopamine, bromocriptine), anticholinergic (scopolamine, diphenhydramine) and GABA-ergic (GABA, muscimol) agents there was a potentiation of the anticatatonic effect. However, clonidine-anticholinergic combination showed a better protective response as compared to clonidine-dopaminergic combination. The protective effect of clonidine and its modification by anticholinergic agents has been explained on the basis of direct central adrenergic as well as central anticholinergic actions of clonidine. Although higher dose of GABA-ergic agents was not studied due to toxicity, the combined effect of clonidine and GABA-ergic agents has been explained on neurotransmitter interactions.