Influence of the neuropeptide galanin on active avoidance in rats.

It was demonstrated in experiments on rats that the injection of the neuropeptide, galanin (200, 500, and 1000 ng), into the lateral cerebral ventricles induced a dose-dependent decrease in the number of successful attempts at avoidance in rats trained preliminarily to active avoidance by jumping. The preliminary administration of the cholinolytic, atropine (1 mg/kg, intraperitoneally), to the rats also caused an acceleration of the damping of the conditioned reflex and potentiated the indicated effect of galanin during the experiment. The use of the opioid antagonist, naloxone (1 mg/kg, intraperitoneally), did not exert an influence on the animals' behavior, but blocked the galanin-provoked acceleration of the extinction of the active avoidance habit. The intraperitoneal administration of a noncompetitive antagonist of excitatory amino acids, ketamine (10 mg/kg), did not influence the character of the animals' behavior nor the indicated effects of galanin. It was concluded that galanin possesses an amnestic action in the active avoidance test, and that this effect of the peptide is determined by the suppression of cholinergic and activation of opiatergic transmission in the central nervous system.