The effect of lysine-vasopressin upon short-term recall of a noxious significance.

This study deals with the effect of vasopressin on the ability to learn (short- and long-term memory) a noxious significance. The literature shows that the response to stress is always accompanied by increased vasopressin secretion. The animals used were 27 adult male rats of which 12 injected with lysine-vasopressin and 15 controls. The effect of the drug was studied on unconditioned avoidance behaviour (light-avoidance) and on learning and retention of an environment the noxious significance of which the animals had trained in a single session. Vasopressin proved to alter, as an immediate effect, the avoidance responsiveness in experimental animals.