Vasopressin impairs or enhances retention of learned submissive behavior in mice depending on the time of application.
The effects of vasopressin on learning and memory were investigated in a paradigm using adaptive capabilities of interacting male mice. Test animals of the DBA/2 strain which were not submissive in a confrontation with a non-aggressive subordinate C57BL/6 mouse on day 1 (baseline), were defeated on day 2 (learning) by an aggressive dominant C57 mouse, and showed learned submissive behavior upon mere contact with a non-aggressive C57 mouse on day 3 (retest). Pretrial injections of lysine-vasopressin (0.01, 0.1 or 1.0 I.U., s.c.) 20 min before defeat on day 2 resulted in less submissive behavior on day 3 compared to controls, with 0.1 I.U. (equal to 370 ng) being the most effective dose. Post-trial injections of vasopressin (0.1 I.U.) immediately after defeat on day 2 significantly improved retention on day 3. Preretention injections of vasopressin (0.1 I.U.) 20 min before testing on day 3 significantly increased learned submissive behavior. The amnesic effect observed after pretrial injections of vasopressin was neither due to state dependency nor to an acquisition deficit, nor to antinociception. It is concluded that processing of the stressful experience of defeat is differently influenced by vasopressin given before or after training, resulting in an impaired or facilitated retention, respectively. Among the hypothetically discussed underlying mechanisms, one suggestion is that exogenous vasopressin interacts with an assumed discriminative stimulus function of endogenously released vasopressin. Another possibility might be that exogenous vasopressin interferes with the defeat-activated opioid peptide system.
D000374:Aggression / Q000187:drug effects; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D004291:Dominance-Subordination; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D012153:Retention, Psychology / Q000187:drug effects*; D012919:Social Behavior; D012930:Social Dominance; D014667:Vasopressins / Q000494:pharmacology*
D014667:Vasopressins