Effect of corticotropin and desglycinamide 9 -lysine vasopressin on suppression of memory by puromycin.

The puromycin-induced blockade of expression of maze learning in mice can be prevented by subcutaneous administration of "Purified Cortrophin Gel" up to 3 days prior to training. A similar protective effect was not found when highly purified corticotropin was tested, but was observed after administration of desglycinamide(9)-lysine vasopressin. It appears that pressorpeptides are more potent protective agents than corticotropin when administered subcutaneously, and that vasopressin contamination of the commercial preparation was probably responsible for the protective effects previously reported. These experiments suggest that vasopressin and its congeners modify memory consolidation in such a way that the "expression" of memory becomes insensitive to puromycin.