Effect of antidepressant drugs on carbachol chloride-induced wet dog shake behaviour in rats

Carbachol chloride, administered intracerebroventricularly, induces a characteristic wet dog-shake response in rats. Wet dog shakes induced by carbachol at a dose of 10 μg were antagonized by amitryptyline, imipramine, desipramine, doxepin, clomipramine and maprotyline (tricyclic antidepressants) in a dose-related manner. Iproniazid, nialamide, tranylcypromine and pargyline (monoamine oxidase inhibitors) also effectively antagonized the wet dog-shake response to carbachol. Amphetamine and nomofensine markedly attenuated wet dog shakes, whilst apomorphine failed to inhibit this carbachol-induced response. It is suggested that carbachol-induced shaking behaviour in rats may be a reliable and convenient model for delineating agents with muscarinic anticholinergic activity. In addition, this behavioural syndrome seems to be of particular importance with respect to the pharmacological profile of antidepressant drugs.