The Efefct And Mechanism Of D1Dopamine Receptor Protected RGC-5Cells From Oxidative Stress Injury

Objective: The objective of this study was to investigate the molecular m-echanismsand signaling pathways that the D1receptor involved to protect retina-l ganglion cell5form H₂O₂-induced damage. Methods: We examined expressi-on of the D1receptor in RGC-5cells with RT–PCR and immunoblotting.Theamplifyed D1receptor sequence is ligated with T-vector.Following the recombi-neant plasmid was identifide by DNA sequence analysis and restriction enzy-me.We also assessed neuroprotection using propidium iodidestaining and the3-（4,5-dim-et-hylt-hiazol-2-yl）-2,5-diphenyltetrazolium bromide assay after H₂O₂-ind-uced damage. In addition, we monitored the activation and involvement of me-mbers of mitogen-activated protein kinases family:extracellular signal-regulatedkinase （ERK）, p38mitogen-activated protein kinase（p38MAPK） and c-Jun NH2-terminal kinase（JNK）, with western blot and specific agonist and inhibitors.Results: We found that the D1receptor was expressed in RGC-5cells, but th -e sequence analysis suggested this cell line is from mouse and not rat origin.SKF83959exhibited a remarkable neuroprotective effect on H₂O₂-damagedRGC-5cells,which was blocked by the specificD1receptor antagonist, SCH233-90. ERK and p38MAPK were activated by SKF83959, and pretreatments withtheir inhibitors U0126and SB203580, respectively,significantly blunted theSKF83959-induced cytoprotection.However,the specific c-Jun NH2-terminal kina-se inhibitor, SP600125,had no effect on the SKF83959-induced protection.Conclusions:We conclude that SKF83959attenuates hydrogen peroxide–inducedinjury in RGC-5cells via a mechanism involving activation of the ERK andp38MAPK pathways and the D1receptor is a potential molecular target fordeveloping neuroprotective drugs.