Behavioral effects of intracerebroventricularly administered neurohypophyseal hormone analogs in mice

The neurohypophyseal hormones oxytocin and vasopressin evoke characteristic behavioral changes after intracerebroventricular injection in mice. These included the induction of excessive grooming and scratching in an unrestricted environment and of escape behavior in stressful situations. The structure-activity relations of 33 neurohypophyseal hormones and hormone analogs in the induction of these behavioral changes were examined. The results demonstrate that these effects generally parallel the vasoconstrictory effects of th peptides. It is suggested that the behavioral effects are mediated by a receptor that is closely related biochemically to the vasopressin receptors in blood vessels. They are not related to the long-term effects of neurohypophyseal hormones on learned behavior. A competitive antagonist of the short-term behavioral effects of these peptides is described. This analog also antagonizes some of the hormonal effects of vasopressin and related peptides.