Figure 1.

Impaired endothelium-dependent relaxations of the renal preglomerular arteries are associated with higher basal O₂⁻ generation in the renal cortex in hyperoxaluric rats (OX) and ameliorated by the SOD mimetic tempol. (A) Comparative endothelium-dependent relaxations of intrarenal arteries levels in control and OX rats. Results are given as a percentage of the phenylephrine (Phe)-induced contraction. Data are means ± SEM of 4 animals (1–2 arteries from each rat). Statistical differences were calculated with unpaired t-test *** p < 0.001. (B) Basal ROS generation in kidney cortex and renal interlobar arteries measured by lucigenin-enhanced chemiluminescence. Results are given as counts per minute (cpm) per mg of tissue. Bars represent mean ± SEM of 5 animals. Statistical differences were calculated with unpaired Student’s t-test *** p < 0.001 versus basal levels. (C,D) Effect of tempol on the relaxant responses elicited by ACh in rat renal interlobar arteries in control (C) and OX groups (D). Statistical differences were calculated by unpaired Student’s t-test ** p < 0.01. (E) Constrictor responses to Phe in renal interlobar arteries from control and hyperoxaluric rats (OX). Results are expressed as absolute values (Nm⁻¹). Data are shown as the mean ± SEM of 7–8 arteries (4 animals).