Quinolinic acid and sigma receptor ligand: effect on pyramidal neurons of the CA1 sector of dorsal hippocampus following peripheral administration in rats.

ABSTRACT

Male Wistar rats, weighing 200-220 g, were used in the study. Quinolinic acid and racemic pentazocine were administered alone or together. Quinolinic acid was administered intraperitoneally (i.p.) in a dose of 60 mmol, racemic pentazocine intramuscularly in a dose of 2 mg/kg, once every 24 h for 8 days. The control group received 1 ml of saline i.p. once daily for 8 days. Pentazocine alone produced no signs of alteration in the hippocampal formation. Quinolinic acid produced neurotoxic effect in the CA1 area of the hippocampal formation. The presence of the dark-degenerated pyramidal cells was a common sign of a delayed excitotoxic effect. Pentazocine added to quinolinic acid markedly attenuated the neurotoxic effect of quinolinic acid. In such cases, only single dark degenerated cells were seen.