[Lewis-x, a sugar chain structure, suppresses the epileptic seizure in El mouse]

El mouse is a mutant strain with genetic epileptogenicity. Epileptic convulsion of El mouse has been shown to be related to metabolical and structural abnormalities in the hippocampal neuron. Gamma-globulin purified from the human serum has a marked anti-convulsive effect in El mouse. Human IgG, 80% of the gamma-globulin, has the reactivity indicating the presence of Lewis-x structure in the sugar chain. In the present study, the author found that 3'-fucosyllactose, the terminal structure of Lewis-x, suppressed the tonic-clonic convulsion of El mouse. Lewis-x is a ligand of granular membrane protein-140 on the surfaces of the vascular endothelial cell and platelet. The vascular endothelial cell and platelet produce platelet-derived growth factor-BB, which prolongs the life-span of the hippocampal neuron and accelerates the formation of its axon and dendrite. The vascular endothelial cell and platelet in El mouse may be activated by 3'-fucosyllactose, and may secrete platelet-derived growth factor-BB, which, in turn, may reduce the sensitivity to have epileptic convulsions in El mouse. Moreover, the author found that the fraction having Lewis-x reactivity obtained from the serum of El mouse had much reactivity of NeuAc alpha 2-6Gal. The sialic acid in Lewis-x structures of El mouse may reduce the ability of the Lewis-x structure to activate the endothelial cell and platelet. The findings in this study indicate that sugar chain structures and their metabolisms are closely related to the mechanism of genetic seizure susceptibility of El mouse.