Effect of reactive oxygen species and nitric oxide in the neural control of intrarenal haemodynamics in anaesthetized normotensive rats

Aims This study examined the interaction between reactive oxygen species and nitric oxide (NO) in mediating the decrease in renal blood flow (RBF) evoked by sympathetic renal nerve stimulation (RNS). Methods Groups of male Wistar rats were subjected to RNS at different frequencies prior to, and following, an infusion of: (i) tempol, the superoxide dismutase (SOD) mimetic, (ii) tempol plus the hydrogen peroxide‐degrading enzyme catalase (tem + cat), (iii) diethyldithiocarbamic acid (DETC), a SOD inhibitor, (iv) the nitric oxide synthase (NOS) inhibitor, L‐nitro‐arginine methyl ester (L‐NAME) alone, or (v) L‐NAME followed by tempol, into the kidney cortico‐medullary border (CMB). Blood perfusion within the cortical (CBP) and medullary (MBP) regions of the kidney was measured using Laser‐Doppler flowmetry. Results Infusion of tempol CMB significantly attenuated RNS‐evoked reductions in CBP (by 22% at 8 Hz; P