Opiate antagonists suppress ACTH(1-24)-induced excessive grooming in the rat.

Intraventricular injection of ACTH(1-24) in rats induces excessive grooming behavior, and subsequent peripheral administration of specific opiate antagonists suppresses this peptide-induced grooming response. Intraventricular injection of morphine mimics both in intact and hypophysectomized rats' - to a certain extent - peptide-induced grooming. The results suggest similarities in the interaction of morphine and ACTH(1-24) with central nervous structures.