Numerous reports suggested possible involvement of Na⁺/K⁺-ATPase in mechanisms of epileptogenesis, especially in hyperhomocysteinemic patients. Proconvulsive and anticonvulsive effects of L – arginine, nitric oxide donor, have been reported. The aim of the present study was to determine the in vivo effects of D,L homocysteine–thiolcatone and L-ariginine on Na⁺/K⁺-ATPase activities in brain stem and hippocampus of adult rats.

Male Wistar rats were divided into following groups: 1) Control (0.9% NaCl), 2) HcyT (8.0 mmol/kg), 3) L- arginine (800 mg/kg) and 4) L-arginine (800 mg/kg) 30 min prior to HcyT (8.0 mmol/kg). All drugs were administered intraperitoneally. Rats were sacrificed 30 min after HcyT administration. The activity of Na⁺/K⁺-ATPase activity was determined in synaptic plasma membranes from rat brain stem and hippocampus. HcyT produced a significant reduction of Na⁺/K⁺-ATPase activity in brain stem and hippocampus by 85.48% (p<0.01) and 83.89% (p<0.01), respectively, when compared with control. On the other hand, L –Arginine increased Na⁺/K⁺-ATPase activity in brain stem and hippocampus by 134% (p<0.01) and 93.35% (p<0.01) comparing to the control. The Na⁺/K⁺-ATPase activity was elevated in brain stem by 103% (p<0.01) and hippocampus by 75% (p<0.01) in rats receiving L-arginine prior to HcyT.

These results indicate that pretreatment with L – arginine reverse reduction of brain Na⁺/K⁺-ATPase activity induced by HcyT in adult rats.