Lithium in combination with haloperidol or thyrotropin-releasing hormone induces jumping in mice

Abstract

Lithium (250 mg/kg IP) administered in combination with haloperidol (2–5 mg/kg IP) or thyrotropin-releasing hormone (TRH) (10 or 20 mg/kg, IP) evoked jumping in mice. Jumping elicited by lithium (250 mg/kg) plus haloperidol (4 mg/kg) or TRH (20 mg/kg) was decreased by physostigmine (0.2 mg/kg IP) and phentolamine (10 mg/kg IP), but was increased by atropine (5 mg/kg IP) and clonidine (0.5 mg/kg IP). While the jumping was not affected by either methylatropine (5 mg/kg IP) or propranolol (10 mg/kg IP). Jumping was also induced by haloperidol (4 mg/kg IP), but not by lithium (250 mg/kg IP), administered after atropine (5 mg/kg IP) or clonidine (0.5 mg/kg IP). The results indicate that lithium plus haloperidol or TRH produces jumping in which dopaminergic and cholinergic inhibition as well as noradrenergic activation may be involved.