OBJECTIVE Angiotensin II (Ang II)-mediated induction of vascular superoxide anion formation could contribute to the development of endothelial dysfunction, hypertension, and atherosclerosis. An NAD(P)H oxidase has been identified as a major endothelial source of superoxide anions. However, the molecular mechanism underlying the regulation of NAD(P)H oxidase activity in response to Ang II is not...

Superoxide anion is the first generated reactive oxygen species (ROS) after oxygen enters living cells. It was once considered to be highly deleterious to cell functions and aging. Therefore, antioxidants were suggested to prevent aging and degenerative diseases. However, superoxide signaling has been shown in many physiological responses such as transcriptional regulation, protein activation, ...

Left lung autotransplantation (LLA) results in a chronic attenuation in endothelium-dependent, nitric oxide (NO)-mediated pulmonary vasodilation. We tested the hypothesis that this abnormality involves a decrease in the effective concentration of NO due to inactivation by superoxide anion. Size- and position-matched pulmonary arterial rings were isolated from the right (control) and left (LLA) ...

Polymorphonuclear leukocytes and other inflammatory cells release superoxide anion and additional oxidant species following stimulation. Corneal endothelial cells were exposed to a flux of chemically generated superoxide anion (oxygen-free radical) produced by the combination of 1 mM hypoxanthine and 0.06 U/ml xanthine oxidase. Exposure of endothelial cells to the combination of hypoxanthine an...

BACKGROUND Using specific antibodies against bovine Cu/Zn-superoxide dismutase (EC 1.15.1.1, SOD1) we demonstrated that anti-SOD antibodies (IgG1) are able to promote the intracellular translocation of the antioxidant enzyme. The transduction signalling mediated by IgG1 immune complexes are known to promote a concomitant production of superoxide and nitric oxide leading to the production of per...

Increased production of superoxide anion may contribute to impaired bioactivity of endothelium-derived nitric oxide in hypertension. Ascorbic acid is capable of scavenging superoxide anion; however, experimental studies have shown that high physiological concentrations (>1 mmol/L) of ascorbic acid are required to prevent superoxide-mediated vascular dysfunction. To seek kinetic evidence that su...

The aim of this study was to determine whether reactive oxygen species (ROS) in the paraventricular nucleus (PVN) mediate both the cardiac sympathetic afferent reflex (CSAR) and angiotensin II-induced CSAR enhancement in chronic heart failure (CHF) rats. CSAR was evaluated from the responses of renal sympathetic nerve activity (RSNA) to epicardial application of bradykinin. In both CHF and sham...