Dose-response relationships in attenuation of puromycin-induced amnesia by neurohypophyseal peptides.

Intracerebral injections of puromycin one day after training of mice in a Y-maze cause amnesia when the animals are tested 7 days later. This amnesia was shown to be attenuated by various neurohypophyseal hormones, analogs and fragments, administered subcutaneously immediately after training. Dose-response relationships have been obtained for the attenuation of puromycin-induced amnesia in mice by selected neurohypophyseal peptides. All of the compounds tested reduce the amnesia in a dose-related way, suggesting that these peptides may interact with specific receptors to induce their central effect. Among the peptides studied the two most potent--i.e., those that cause substantial retention of memory at the lowest doses--are the neurohypophyseal hormone arginine vasopressin and Z-prolyl-leucyl-glycinamide (Z-MIF).