INVOLVEMENT OF DOPAMINERGIC RECEPTORS IN QUINOLINATE-INDUCED STRIATALLESIONS

THE purpose of this study was to examine the effects of blockade (sulp iride) and activation (quinpirole) of dopaminergic D2 (DA2) receptors on brain lesions subsequent to excessive activation of glutamate (GLU) receptors. Striatal lesions were produced by direct injection of quin olinic acid, an endogenous GLU receptor agonist. Sulpiride (100 mg kg- 1 i.p., 30 min before quinolinic acid injection and 1 h after) signifi cantly (p less-than-or-equal-to 0.05) reduced the volume of the lesion by around 20%. Quinpirole (1.25 mg kg-1 i.p., 30 min before quinolini c acid injection) had no effect. The protective action of DA2 receptor blockade strongly suggests that quinolinic acid-induced excitotoxicit y may be partly modulated by DA2 receptors.