Effect of lysine vasopressin on pentylenetetrazol-induced retrograde amnesia in rats.

Lysine vasopressin (1 microgram/rat SC) administered 1 hr prior to either the acquisition trial or 24 hr retention trial facilitated passive avoidance retention. Amnesia was produced when a single 50 mg/kg (IP) injection of pentylenetetrazol was given immediately following the passive avoidance acquisition trial. A single injection of lysine vasopressin (1 microgram/rat SC) administered 1 hr prior to either the acquisition trial or 24 hr retention trial antagonized the amnesia.