Facilitation of active avoidance responding following chronic haloperidol treatment in rats

Rats were chronically treated with once-daily injections of either haloperidol or vehicle for 21 days. When spontaneous locomotor activity or acquisition of active avoidance in a two-way shuttle box were measured 48 h after the cessation of chronic treatment, the haloperidol-treated animals were significantly more active and performed significantly more avoidance responses. These findings suggest that the increased dopamine receptors that have been reported following chronic haloperidol treatment may have functional relevance.