THE ROLE OF ENDOGENOUS VASOPRESSIN AND OXYTOCIN IN RESTRICTED BRAIN-AREAS ON PASSIVE-AVOIDANCE BEHAVIOR

Local application of antiserum against vasopressin in a 1 : 50 dilution in the dorsal raphe nucleus attenuates passive avoidance behavior of rats when micro-injected either immediately after the learning trial or prior to retention. A similar micro-injection into the lateral habenular region attenuates passive avoidance only upon preretention treatment, but not when given post-learning. Local application of anti-oxytocin serum in the dorsal hippocampal/dentate gyrus area, in the dorsal raphe nucleus or in the lateral habenular region does not affect passive avoidance behavior. It is concluded that the local presence or release of endogenous vasopressin in the dorsal raphe nucleus plays a role in memory processes related to storage as well as retrieval of information, whereas endogenous vasopressin in the lateral habenular region is only involved in retrieval.