The effect of various antidepressant drugs upon the tetrabenazine-suppressed conditioned avoidance response in rats

Rats were trained in a three-chambered discrimination box to avoid an electric shock which was preceded by the presentation of light. Tetrabenazine, at a subcutaneous dose of 6 mg/kg suppressed this conditioned avoidance response (CAR) without abolishing the unconditioned escape response (UER). The three classes of antidepressant drugs affected differently the tetrabenazine-induced suppression of CAR. The tricyclic antidepressants, imipramine and desmethylimipramine (DMI), did not prevent the suppression of the CAR while the monoamine oxidase (MAO) inhibitors, iproniazid and pargyline did. The stimulant drugs d-amphetamine and methylphenidate, in addition to preventing also reversed the effect of tetrabenazine. The action of two experimental compounds, butriptyline and Lu3-010 was also investigated.