Repeated treatment with amitriptyline reduces immobility in the behavioural ‘despair’ test in rats by activating dopaminergic and β-adrenergic mechanisms

Abstract

Abstract Seven days of treatment with amitriptyline 10 mg kg−1 day−1, reduced the immobility time in the behavioural ‘despair’ test in rats. 0.5, but not 0.25 mg kg−1 haloperidol significantly counteracted the reduction of immobility caused by amitriptyline. Its anti-immobility effect was reduced by 50 and 100 mg kg−1 sulpiride, another blocker of dopamine receptors, and 5 mg kg−1 (±)-propranolol, a β-adrenolytic drug. Prazosin, 3 mg kg−1, an antagonist of post-synaptic α-adrenoceptors, had no effect. It is suggested that dopaminergic and β-adrenoceptors mediate the anti-immobility effect of repeated amitriptyline treatment in rats.