Quinolinic acid and GABA-B receptor ligand: effect on pyramidal neurons of the CA1 sector of rat's dorsal hippocampus following peripheral administration.

In this study we evaluated the effect of baclofen on excitotoxic action of quinolinic acid in hippocampus following its prolonged systemic administration in rats. Male Wistar rats, weighing 200-220 g, were used in the study. Quinolinic acid and baclofen were administered alone or together. Quinolinic acid was administered intraperitoneally (i.p.) in a dose of 60 mmol, baclofen in a dose of 2 mg/kg, by gastric tube, once daily for 8 days. The control group received 1 ml of saline i.p. once daily for 8 days. Quinolinic acid alone 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. Baclofen added to quinolinic acid markedly attenuated the neurotoxic effect of quinolinic acid. In such cases, only some dark degenerated cells were seen. Baclofen alone resulted in alterations in some pyramidal cells in the hippocampal formation.