L-prolyl-L-arginyl-glycineamide induces memory enhancement in chicks

Two-day-old chicks were injected either intraventricularly or intraperitoneally with saline or a L-prolyl-L-arginyl-glycineamide solution. This C-terminal tripeptide of arginine vasopressin produced dose dependent enhancement effects when injected centrally but not peripherally. Physical debilitation and/or aversive effects of the peptide were eliminated as the cause of the decreased responding noted in memory enhancement studies using this avoidance paradigm. Possible memory mechanisms are discussed in light of this peptide's relationship to vasopressin, vasotocin, and L-propyl-L-leucyl-glycineamide.