Actions of antidepressant and neuroleptic drugs on ACTH- and novelty-induced behavior in the rat.

The present study deals with the effects of psychoactive drugs (neuroleptics and antidepressants) on ACTH-induced excessive grooming in the rat. The neuroleptics haloperidol and clozapine and the antidepressants amitriptyline, nomifensine and mianserin all suppressed the grooming response in a dose-dependent manner. The neuroleptic sulpiride was ineffective even at high doses. Experimental evidence is presented suggesting that the suppression of peptide-induced grooming was not the result of competing behavioral activity elicited by the drug itself. Instead it is assumed that the psychoactive drugs tested affected directly the activity of the neural substrate underlying the peptide-induced behavior. In view of the complexity of the mechanisms of action of the drugs tested it is argued that this substrate may be a more complex one than the dopamine systems as suggested before.