High doses of clonidine elicit jumping behavior in the mouse

Neuronal mechanisms involved in the jumping produced by high doses of clonidine were studied in adult mice. Intraperitoneal administrations of clonidine at doses ranging from 10 to 40 mg/kg elicited jumping behavior in dose-dependent manner, the highest frequency of jumping being observed at a dose of 30 mg/kg. The jumping behavior induced by clonidine (30 mg/kg) was decreased by pretreatment with physostigmine (0.2 mg/kg IP), apomorphine (2 mg/kg IP) and phentolamine (10 mg/kg IP), and conversely increased by atropine (5 mg/kg IP), apomorphine (0.25 mg/kg), haloperidol (2 mg/kg IP) and propranolol (10 mg/kg IP). The jumping behavior was unaffected by methylatropine (5 mg/kg IP) and mecamylamine (0.1 mg/kg IP). In addition, N6-cyclohexyl adenosine (0.2 mg/kg IP) or diazepam (2 mg/kg IP) did not affect, either. The result suggests that high doses of clonidine elicit jumping in which alpha-adrenoceptor activation, dopaminergic and cholinergic inhibition are concomitantly involved.