Nitric oxide synthase inhibitors protect cerebellar Purkinje cells from zinc-induced cell loss in adult rat

Abstract Zinc is an important trace element in biological systems; however, excessive extracellular zinc could lead to neuronal cell death following ischemia, seizures, and brain trauma. In this study, we investigated whether the intracortical injection of zinc sulphate (200 μg/kg, i.c.) changes total number of Purkinje cells in the cerebellum and whether different types nitric oxide synthase inhibitors, N-(G)-nitro- l -arginine methyl ester ( l -NAME), N(omega)-nitro- l -arginine ( l -NNA), aminoguanidine and 7-nitroindazole (7-NI), have protective effects against zinc neurotoxicity in Wistar albino rats. Animals were divided into 6 groups: control, zinc, zinc +  l -NAME (100 mg/kg, i.p.), zinc +  l -NNA (100 mg/kg, i.p.), zinc + 7-NI (100 mg/kg, i.p.) and zinc + aminoguanidine (100 mg/kg, i.p.) groups. Total number of Purkinje cells in the cerebellum was estimated using unbiased stereological technique as 318,947 ± 20,549, 123,483 ± 23,762, 206,537 ± 43,128, 178,135 ± 26,635, 193,148 ± 46,104 and 212,910 ± 26,399 in the control, zinc, zinc +  l -NAME, zinc +  l -NNA, zinc + 7-NI and zinc + aminoguanidine groups, respectively (mean ± SD). The number of Purkinje cells in zinc group was significantly lower than that of the other groups ( P