Alleviation of anisomycin-induced amnesia by pre-test treatment with lysine- vasopressin.

Amnesia in mice for a passive avoidance response induced by anisomycin injection immediately after training was reversed by 40 micrograms of lysine-vasopressin given one hour before testing. Control groups receiving non-contingent shock instead of training were used to demonstrate that the effects of vasopressin were due to memory of shock received in a particular place, rather than non-specific suppression of locomotion. The effects of vasopressin on retention were not mimicked by either pentylenetetrazol or epinephrine suggesting that the enhanced latencies were probably not the result of increases in fear or arousal. These data support the hypothesis that the retrieval of memory can be facilitated by vasopressin. The possibility of a relationship between the effects of vasopressin and those of catecholamine manipulations on memory is discussed.