Haloperidol-induced catalepsy: a model for screening antidepressants effective in treatment of depression with Parkinson's disease.

Incidence of severe depression is very common in Parkinson's disease (PD). Use of antidepressants in such cases is known to improve or worsen the existing PD. However, prediction of the effect of antidepressant on symptoms of PD is limited due to lack of suitable animal model. The present study examines the possibility of using haloperidol-induced catalepsy model in rats for this purpose. Antidepressants showed distinct effect on haloperidol-induced catalepsy, although most of them reduced forced-swimming induced immobility. In general, antidepressants with greater noradrenergic reuptake inhibition (desipramine, imipramine, amitriptyline, nortriptyline, protriptyline and maprotiline) reduced, whereas those with serotonergic reuptake inhibition (fluoxetine and clomipramine) increased haloperidol-induced catalepsy. Mianserin, an atypical antidepressant, and alprazolam, a benzodiazepine receptor analogue had no effect on haloperidol-induced catalepsy. The results suggest that haloperidol-induced catalepsy model in rats needs to be incorporated in the screening procedure when evaluating the utility of antidepressant drugs for the treatment of depression associated with PD.