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Effect of reactive oxygen species and nitric oxide in the neural control of intrarenal haemodynamics in anaesthetized normotensive rats
Author(s) -
Ahmeda A. F.,
Rae M. G.,
Johns E. J.
Publication year - 2013
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12150
Subject(s) - nitric oxide , catalase , reactive oxygen species , chemistry , superoxide dismutase , nitric oxide synthase , superoxide , hydrogen peroxide , endocrinology , kidney , medicine , pharmacology , oxidative stress , biochemistry , enzyme , organic chemistry
Abstract 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 < 0.05), but not MBP . When tempol and catalase were co‐infused to reduce both ROS and hydrogen peroxide (H 2 O 2 ), respectively, there was a significantly greater attenuation of the RNS ‐evoked reduction in CBP compared with that of tempol alone. Infusion of either DETC or L ‐ NAME alone did not significantly affect the CBP or MBP responses to RNS. Similarly, RNS following tempol infusion with L ‐ NAME also had no effect on CBP and MBP over and above the group that received tempol alone. Conclusion These results suggest that reactive oxygen species such as superoxide and H 2 O 2 have a direct role in reducing renal vascular compliance in response to RNS , rather than indirectly through scavenging NO .