pituitrin and prolyl-lysyl-glycinamide

[Ile3, Arg8]vasopressin (arginine-vasotocin), as well as the C-terminal tripeptides of the neurohypophyseal hormones arginine and lysine vasopressin, Pro-Arg-Gly-NH2 and Pro-Lys-Gly-NH2, were protective against puromycin-induced amnesia in mice when administered 24h before training. The N-protected tripeptide derivative, Z-Pro-Lys-Gly-NH2, was effective when given 5 days before training. The effectiveness of all peptides to attenuate puromycin-induced amnesia decreased as the interval between training and peptide treatment increased, indicating that the peptides influence memory processes, rather than general arousal. Z-Pro-Lys-Gly-NH2 was active at 24h after training, when the other peptides were no longer effective. Although it seems clear that neurohypophyseal hormones per se can attenuate puromycin-induced amnesia, these results are in line with the possibility that some portion of hormone action may be mediated via formation of longer-lived hormone fragments in the CNS.

Topics: Amnesia; Animals; Arginine; Arginine Vasopressin; Humans; Hypothalamus; Memory; Mice; Neurophysins; Oligopeptides; Puromycin; Time Factors; Vasopressins