Methylcobalamin protects against glutamate-induced neurotoxicity in retinal cell culture. - GreenMedInfo Summary
Protective effects of methylcobalamin, a vitamin B12 analog, against glutamate-induced neurotoxicity in retinal cell culture.
Invest Ophthalmol Vis Sci. 1997 Apr;38(5):848-54. PMID: 9112980
Department of Ophthalmology, Graduate School of Medicine, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
PURPOSE: To examine the effects of methylcobalamin on glutamate-induced neurotoxicity in the cultured retinal neurons. METHODS: Primary cultures obtained from the fetal rat retina (gestation days 16 to 19) were used for the experiment. The neurotoxicity was assessed quantitatively using the trypan blue exclusion method. RESULTS: Glutamate neurotoxicity was prevented by chronic exposure to methylcobalamin and S-adenosylmethionine (SAM), which is formed in the metabolic pathway of methylcobalamin. Chronic exposure to methylcobalamin and SAM also inhibited the neurotoxicity induced by sodium nitroprusside that release nitric oxide. By contrast, acute exposure to methylcobalamin did not protect retinal neurons against glutamate neurotoxicity. CONCLUSIONS: Chronic administration of methylcobalamin protects cultured retinal neurons against N-methyl-D-aspartate-receptor-mediated glutamate neurotoxicity, probably by altering the membrane properties through SAM-mediated methylation.