N-methyl-D-aspartic acid injected peripherally stimulates oxytocin and vasopressin release

The effects of N-methyl-D-aspartic acid (NMDA), injected s.c. or i.p. in the dose range of 2.5-10 mg/kg, on oxytocin and vasopressin levels were assessed in conscious rats. NMDA administration was found to induce a dose-related increase in oxytocin concentration with a peak response at 7.5 min. Plasma vasopressin was elevated only after injection of the highest dose used (10 mg/kg). Thus, though at different thresholds, the release of both posterior pituitary hormones was stimulated after NMDA administration.