Differential enhancement of locomotor activity by dopamine agonists following chronic neuroleptic treatment: an animal model of tardive dyskinesia.

Animals were administered clozapine or haloperidol for 22 days. Following treatment they were challenged with an apomorphine ester or lergotrile. Only haloperidol-treated animals exhibited significantly enhanced responses to apomorphine ester whereas administration of lergotrile potentiated locomotor activity in both treated groups. The results suggest that the use of different dopaminergic agonists may help to dissociate receptor supersensitivity arising from the antipsychotic actions of neuroleptics from that leading to the development of undesirable side effects.