Neuroprotection for Cell Death of Retinal Ganglion Cells and Molecular Biological Study for Nervi-Regeneration

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NMDA, AMPA and kainate receptors were confirmed to exist on MACS-separated cultured RGC. Moreover, 20-HE inhibited NMDA receptor-mediated currents most prominently and AMPA- and kainate-mediated currents moderately.cDNA arrays were used to detect highly expressed mRNA in the mouse eye. We focused among them on a novel gene, ODAG (GenBank ; Accession No.AB047921), which was downregulated at P10. Mouse ODAG cDNA encodes a protein of 266 amino acids. Human ODAG cDNA and genomic structure were identified by BLAST analysis of the GenBank database with mouse ODAG. Mouse ODAG-specific mRNA expression was detected in various mouse tissues within the eye at P2 and P7, whereas it was not detected anywhere at P14.Expression of isoforms of nitric oxide synthase (NOS), enzymes responsible for NO production, and the synthesis of nitric oxide (NO) in rat retinal ganglion cells (RGCs) induced by glutamate stimulation were investigated. Immunohistochemical analysis revealed nNOS and eNOS expressed in r … More etinal ganglion cells. Intracellular NO levels in cultured RGCs showed fluctuation during a 20-minute observation. The presence of a specific nNOS inhibitor significantly inhibited the increase of intracellular NO after the introduction of glutamate to fee medium. This study revealed that all constitutive NOS isoforms are expressed in RGCs, and demonstrated that NO is produced by nNOS mainly that is stimulated by glutamate in cultured RGCs.Glutamate caused cell death to retinal ganglion cell for 24 hrs in a concentration-dependent manner. Glutamate increased in intracellular Ca^<2+> concentration ([Ca^<2+>]_i) in a concentration-dependent manner. NMDA and KCl caused the same results. Betaxolol inhibited the KCl-induced increase in [Ca^<2+>]_i to 25 %. On the other hand, betaxolol significantly inhibited glutamate-induced RGCs death. An increase in [Ca^<2+>]_i is considered the first signal of glutamate neurotoxicity. Betaxolol produced the neuroprotective effects by inhibiting voltage-dependent calcium channels. This method is probably useful for searching neuroprotective drugs and new glaucoma therapy. Less