Effects of monosialoganglioside on a new model of tardive dyskinesia

1- The effects of monosialoganglioside GM(1) were studied on a new model of tardive dyskinesia, i.e., the frequency of spontaneous tongue protrusions in rats repeatedly treated with reserpine. 2- Rats were co-treated with vehicle (VEH) or reserpine (RES) (0.1 mg/kg, sc, every other day) and saline (SAL) or GM1 (5 mg/kg, ip, every day) for 30 days and observed for tongue protrusions on days 10, 20 and 30. 3- During each test day animals of the RES+SAL, group exhibited an increase in tongue protrusions relative to rats of the VEH+SAL group. However, rats of the RES+GM(1) group showed an increased frequency of tongue protrusions only on day 10, when compared to animals of the VEH+SAL group. There were no significant differences in tongue protrusion frequency between the VEH+GM(1) and the VEH+SAL groups. 4- These results differ from previous studies which reported a facilitatory effect of GM1 coadministration on conventional behavioral animal models of tardive dyskinesia: The possibility is raised that GM1 attenuates the reserpine-induced increase in tongue protrusions through its protective effect on glutamate/oxidative stress neurotoxicity.