Influence of quinolinic acid, an endogenous neurotoxin, on a passive avoidance conditioned reflex in rats.

Quinolinic acid, an endogenous neurotoxin, was introduced into the cerebral ventricles of a rat in doses of 0.5 microgram and 30 micrograms. The influence of the substance on the reproduction of a passive avoidance conditioned reflex (CR) was evaluated. It was found that a small dose of the preparation decreases extinction, while a large dose disrupts the reproduction of a passive avoidance CR. The disruption of the reproduction of the skill was also observed after bilateral electrolytic destruction of the dorsal hippocampus. Quinolinic degeneration of this structure exerted a substantial influence on the reproduction of a passive avoidance CR.