The effects of ACTH- and vasopressin-analogues on CO2-induced retrograde amnesia in rats

Abstract

Amnesia for a one-trial step-through passive avoidance response was induced in rats by application of CO2 until respiratory arrest occurred. The ACTH-analogue ACTH4–10 alleviated the amnesia when administered 1 hr prior to the retrieval test but not when given 1 hr prior to the acquisition trial. The behaviourally inert ACTH-analogue ACTH11–24 appeared to have no effect on the amnesia. The vasopressin-analogue desglycinamide lysine vasopressin (DG-LVP) antagonized the amnesia when administered 1 hr prior to the acquisition trial or 1 hr prior to the test trial. The relevance of these date to present theories on amnesia is discussed.