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Endogenous nitric oxide minimizes vasoconstriction during low frequency renal sympathetic nerve stimulation
Author(s) -
Kretzer Julie,
Collett Jason,
O'Brien Michelle,
Osborn Jeffrey
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.804.13
Subject(s) - vasoconstriction , constriction , stimulation , nitric oxide , kidney , medicine , renal circulation , medullary cavity , renal blood flow , reflex , endogeny , chemistry , endocrinology , anesthesia
Low frequency renal nerve stimulation (LFRNS) decreases medullary (MBF) and cortical (CBF) blood flows. The impact of endogenous nitric oxide (NO) on LFRNS mediated changes in MBF and CBF was determined in anesthetized Sprague Dawley (SD) rats. Animals (n=13) were anesthetized and Laser Doppler flow probes were positioned on or below the kidney surface to measure CBF and MBF. After control, LFRNS was conducted at 0.5 and 1.5 Hz for 15 minutes each. LFRNS (0.5 Hz) decreased MBF by ‐1.89 ± 0.39% and CBF by ‐2.12 ± 0.77% of control. At 1.5 Hz, LFRNS decreased MBF and CBF by ‐8.70+2.31% and ‐10.84 ± 3.7% of control, respectively. Following a 30 minute recovery period from LFRNS, L‐arginine (L‐ARG; 300 ug/kg/hr, i.v.) was infused for 30 minutes and LFRNS was repeated. L‐ARG infusion did not change control MBF or CBF but abolished renal vasoconstriction elicited by 0.5 Hz LFRNS. Furthermore, 1.5 Hz LFRNS mediated vasoconstriction was attenuated in both medullary and cortical regions (‐3.75 ± 1.78% and ‐6.87 ± 2.67%, respectively; p<0.05 vs. control constrictor responses). Thus, endogenous NO significantly decreases renal vascular constriction during LFRNS in renal medullary and cortical vessels. NO may provide protection against both cortical and medullary vasoconstriction during small and subtle changes in renal sympathetic outflow. (Supported by an APS Predoctoral Fellowship to J. Kretzer and UK Biology Ribble Foundation).