Antioxidant pyrrolidine dithiocarbamate prevents defective bradykinin- stimulated calcium accumulation and nitric oxide activity following exposure of endothelial cells to elevated glucose concentration

Abstract

Previous studies from our laboratory suggest that reactive oxygen contributes to diminished bradykinin-stimulated calcium accumulation in endothelial cells exposed to elevated glucose concentrations. In this study, we evaluated the efficacy of the antioxidant pyrrolidine dithiocarbamate (PDTC), in preventing defects in intracellular calcium signalling and nitric oxide (NO) activity in endothelial cells exposed to elevated glucose concentration. We show that PDTC prevented the elevated glucose-induced impairment in bradykinin-stimulated calcium accumulation without changing the normal calcium accumulation in response to ionomycin. Furthermore, the impaired cyclic GMP in RFL-6 detector cells (an index of NO activity) generated by bradykinin-stimulation of high glucose-exposed endothelial cells was restored to normal by pretreatment with PDTC. These studies support a role of reactive oxygen in elevated glucose-induced defects in calcium signalling and NO activity by endothelial cells and that antioxidants may be useful in preventing this defect.