Abstract P081: Tempol Decreases Blood Pressure in Aged Female SHR When Treated With Acetazolamide

Oxidative stress contributes to the development and maintenance of hypertension in male rodents, but studies in females have rarely shown a reduction in blood pressure (BP) with antioxidants. Tempol, a superoxide dismutase mimetic, decreases BP in young male SHR, but fails to reduce BP in either young or old female SHR, despite the fact that females have similar or higher levels of oxidative stress markers. The reason for the sex difference in the response to tempol remains unclear. Acetazolamide inhibits carbonic anhydrase in the proximal tubule thus increasing sodium delivery to the distal nephron, and thereby should increase distal oxidative stress. Acetazolamide was used to test the hypothesis that with increased sodium delivery to the distal nephron, tempol would reduce the BP in aging female SHR. Female SHR, 20-22 mos old, were divided into three groups (n=4-6/grp): Control (C), Acetazolamide (A), and Acetazolamide+Tempol (A+T). After baseline mean arterial pressure (MAP; telemetry), rats received vehicle (C) or acetazolamide (A and A+T). On day 8, rats in C and A+T groups were given tempol (30 mg/kg) for 11 days. Baseline MAP was similar (C: 170±7; A: 182±4; A+T: 172±6 mm Hg, p=NS). Tempol had no effect on MAP in C+T, but reduced MAP in A+T group (C+T: 169±1; A: 171±1; A+T: 151±5 mm Hg; p