Vasopressin-induced motor disturbances: localization of a sensitive forebrain site in the rat.

Arginine-vasopressin (AVP) microinjected into an area extending from the diagonal band of Broca to the anterior hypothalamus of the rat evokes severe motor disturbances, including barrel rotations and myoclonic/myotonic movements. These disturbances do not occur after administration of an artificial physiological solution or of oxytocin. Injection of this peptide into other areas of the brain does not cause these effects. This action of vasopressin is dose-related, can be prevented by the prior administration of an AVP receptor antagonist and involves a 'sensitization' process. It is possible that AVP, acting in this mediobasal region of the forebrain, might be involved as a causative agent in some convulsive disorders.