Cafer Marangoz and Faruk Bagirici*
Department of Physiology, Faculty of Medicine, University of Ondokuz Mayis, 55139 Samsun, Turkey
*Corresponding author. FAX: +90-362-457-6093, E-mail: fbagirici@yahoo.com
Abstract: It has been suggested that nitric oxide (NO) is involved in the pathophysiology of epilepsy. Data are, however controversial because it is not clear whether NO has pro- or anticonvulsant effects. The aim of this study was to investigate the effects of NO on penicillin G-induced epileptiform activity. The left cerebral cortex was exposed by craniotomy in urethane-anesthetized Wistar rats. The epileptic activity was produced by intraperitoneal injection of penicillin G (3 million U/kg, i.p.). The ECoG (electrocorticogram) activity was displayed on a four-channel recorder. At 39.7 ± 5.4 min after penicillin administration, large amplitude sharp waves appeared in the ECoG. Mean spike frequency and mean spike amplitude were calculated as 29.5 ± 3.2/min and 865 ± 91 mV, respectively, at the 55th min. 7-Nitroindazole (60 mg/kg, i.p.) injection 30 min before penicillin G administration significantly reduced the latency of epileptiform activity. Intracerebroventricular administration of L-arginine (300 mg/2 ml, i.c.v.) and sodium nitroprusside (100 mg/2 ml, i.c.v.) suppressed epileptiform activity. Saline (2 ml) and D-arginine (300 mg/2 ml, i.c.v.) administration into the cerebral ventricle were completely ineffective on epileptiform activity (P<0.01). These findings suggest that NO may be an endogenous antiepileptic substance.
Keywords: Nitric oxide, L-Arginine, Sodium nitroprusside, 7-Nitroindazole, Epileptiform activity, Penicillin
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