GMI ganglioside prevents seizures, Na+,K+-ATPase activity inhibition and oxidative stress induced by glutaric acid and pentylenetetrazole

Abstract

Monosialoganglioside (GM1) is a glycosphingolipid that protects against some neurological conditions, such as seizures and ischemia. Glutaric acidemia type I (GA-I) is an inherited disease characterized by striatal degeneration, seizures, and accumulation of glutaric acid (GA). in this study, we show that GA inhibits Na+,K+-ATPase activity and increases oxidative damage markers (total protein carbonylation and thiobarbituric acid-reactive substances-TBARS) production in striatal homogenates from rats in vitro and ex vivo. It is also shown that GM1 (50 mg/kg, i.p., twice) protects against GA-induced (4 mu mol/striatum) seizures, protein carbonylation, TBARS increase, and inhibition of Na+,K+-ATI`ase activity ex vivo. Convulsive episodes induced by GA strongly correlated with Na+,K+-ATPase activity inhibition in the injected striatum but not with oxidative stress marker measures. Muscimol (46 pmol/striatum), but not MK-801 (3 nmol/ striatum) and DNQX (8 nmol/striatum) prevented GA-induced convulsions, increase of TBARS and protein carbonylation and inhibition of Na+,K+-ATPase activity. the protection of GM1 and muscimol against GA-induced seizures strongly correlated with Na+,K+-ATPase activity maintenance ex vivo. in addition, GM1 (50-200 mu M) protected against Na+K+-ATPase inhibition induced by GA (6 mM) but not against oxidative damage in vitro. GM1 also decreased pentylenetetrazole (PTZ)-induced (1.8 mu mol/striatum) seizures, Na+,K+-ATPase inhibition, and increase of TBARS and protein carbonyl in the striatum. These data suggest that Na+,K+-ATPase and GABA(A) receptor-mediated mechanisms may play important roles in GA-induced seizures and in their prevention by GM1. (c) 2006 Elsevier Inc. All rights reserved.