title: Protective effects of methylcobalamin, a vitamin B12 analog, against glutamate-induced neurotoxicity in retinal cell culture.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kikuchi
authors.forename: S
authors.initials: S
authors.lastname: Kashii
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: Y
authors.initials: Y
authors.lastname: Tamura
authors.forename: K
authors.initials: K
authors.lastname: Kaneda
authors.forename: A
authors.initials: A
authors.lastname: Akaike
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D004396:Coloring Agents; D018698:Glutamic Acid / Q000633:toxicity*; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D009599:Nitroprusside / Q000633:toxicity; D051381:Rats; D012160:Retina / Q000166:cytology / Q000187:drug effects* / Q000196:embryology; D012436:S-Adenosylmethionine / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000633:toxicity; D014343:Trypan Blue; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004396:Coloring Agents; D013439:Sulfhydryl Reagents; D009599:Nitroprusside; D018698:Glutamic Acid; D012436:S-Adenosylmethionine; C019476:mecobalamin; D014343:Trypan Blue; D014805:Vitamin B 12; D002118:Calcium