INDUCTION OF AROUSAL IN HIBERNATING EUROPEAN HAMSTERS (CRICETUS-CRICETUS L) BY VASOPRESSIN INFUSION IN THE LATERAL SEPTUM

Vasopressin immunostaining in the lateral septum of the European hamst er (Cricetus cricetus L.) disappears in autumn, at the time of the fir st appearance of hypothermic periods characteristic to hibernation. Pr evious results have shown that chronic administration of vasopressin i n the lateral septum during winter prevents the expression of hypother mic periods, suggesting a role for this peptide in hibernation. It is now observed that acute infusion of vasopressin, and in 50% of the cas es, of a specific vasopressin V-1 receptor agonist, during a hypotherm ic period results in an immediate termination of hypothermia. Infusion of oxytocin or a vasopressin V-2 receptor agonist were without effect . The results indicate that the seasonal variation in central vasopres sin activity, possibly through an interaction with V-1 receptors, may play an important role in the expression of hibernation in the Europea n hamster.