Behavioural data on dermorphins in mice.

Dermorphin, an opioid peptide occurring in amphibian skin, exerted a depressive effect on locomotor activity of C57B1/6 mice and an analgesic effect when injected intravenously. Intracerebroventricular injections of dermorphin enhanced locomotor activity and resulted in analgesia. A stimulating effect of intracerebroventricular administration on locomotor activity was also induced by shorter homologues of dermorphin and [D-Ala2, Leu5]enkephalinamide, while beta-endorphin produced a depression. It is suggested that dermorphin acts on central receptor populations activated by morphine and enkephalins.