Intraventricular injection of antivasopressin serum blocks learned helplessness in rats

An experiment was conducted to test further the role of vasopressin in memory processes, using the learned helplessness paradigm as the memory testing situation. Mice treated intraventricularly with control rabbit serum immediately after an initial period of inescapable preshocks showed subsequent deficits in learning an escape task, a replication of the learned helplessness phenomenon. However, mice treated intraventricularly with antiserum to vasopressin after the initial inescapable shocks did not show later escape deficits. These findings are interpreted as supporting the suggestion that endogenous vasopressin is involved in long-term memory.