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Renal nerves and nNOS: Roles in natriuresis of acute sodium loading
Author(s) -
Wolff H,
KompanowskaJezierska E,
Bie P
Publication year - 2006
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.20.4.a333-a
Subject(s) - natriuresis , denervation , medicine , endocrinology , sodium , saline , chemistry , plasma renin activity , tonicity , renin–angiotensin system , kidney , blood pressure , organic chemistry
We investigated the role of renal nerves and nNOS in the response to acute, mild sodium loading in conscious Sprague‐Dawley female rat. Animals were subjected either to bilateral renal denervation or sham‐operated. The rats were permanently provided with arterial, venous and bladder catheters. Denervated and sham rats were exposed to a hypertonic saline load (50 μmol/kg/min, 120 min.) with and without treatment with a nNOS inhibitor, S‐methylthiocitrulline (SMTC, 20 μg/kg/min). Control experiments included isotonic infusion at the same flow of 25 μl/kg/min. Renal denervation decreased MABP (101±2 vs. 112±2 mmHg, mean±SE). SMTC treatment increased MABP in both denervated and sham rats to 110±2 and 118±2 mmHg, respectively. Denervated rats had lower plasma renin concentration (PRC) than sham (14±1 vs. 20±1 mIU/L). The control value of inulin clearance for denervated rats was lower than for sham (2.2±0.2 vs. 2.6±0.1 ml/min). Sodium loading increased MABP similarly in all situations (6‐9 mmHg). SMTC treatment lowered PRC control values in sham rats to values similar to denervated. A progressive increase in PAH clearance during sodium loading was absent in both groups with SMTC treatment. In contrast to denervated rats, the treatment of sham rats with SMTC augmented the natriuretic response to the sodium load to a peak value of 16±2 μmol/min compared to 12±1 μmol/min. It is concluded (i) that the renal nerves are unimportant to the present natriuretic response but mediate a tonic pressor effect on MABP, and (ii) that the reputed nNOS inhibitor blunts the renal hemodynamic and augments the natriuretic response to an acute sodium load. Supported by The Danish Research Council