ROLE OF RENAL NERVES IN SODIUM RETENTION OF CIRRHOSIS AND CONGESTIVE-HEART-FAILURE

To define the role of renal nerves in renal Na retention of cirrhosis and congestive heart failure (CHF), experiments were done in rats with cirrhosis due to common bile duct ligation (CBDL) and CHF due to myocardial infarction from left coronary artery ligation. Two weeks after induction of CBDL or CHF, diseased and sham diseased (Sham) rats were subjected to bilateral renal denervation (DNX) or sham renal denervation (innervated. INN). Five days after DNX or INN, 26-day metabolic balance studies were carried out in all rats. Daily dietary Na intake averaged 2.0-3.0 meq/day on days 1-6 and 22-26 and averaged 0.120 meq/day on days 7-21. Cumulative Na balance was greater in CBDL and CHF rats, INN or DNX, than in Sham/CBDL or CHF rats throughout the study. On day 6 at the end of the normal dietary Na intake period (days 0-6), cumulative Na balance was not affected by renal denervation in Sham/CBDL or CHF rats (INN, 2.02 +/- 0.19 meq, n = 10; DNX, 2.04 +/- 0.17 meq, n = 11), CBDL rats (INN, 4.21 +/- 0.39 meq, n = 10; DNX, 3.78 +/- 0.37 meq, n = 10), or CHF rats (INN, 3.74 +/-0.72 meq, n = 9; DNX, 3.22 +/- 0.55 meq, n = 10). On day 21, at the end of the low dietary Na intake period (days 7-21), cumulative Na balance was not affected by renal denervation in Sham/CBDL or CHF (INN, 1.53 +/- 0.23 meq; DNX, 1.54 +/- 0.26 meq) but was significantly decreased (P < 0.05) by renal denervation in CBDL (INN, 4.05 +/- 0.38 meq; DNX, 2.61 +/- 0.27 meq) and CHF (INN, 3.72 +/- 0.72 meq; DNX, 1.91 +/- 0.48 meq). On day 26 at the end of the normal dietary Na intake period (days 22-26), which concluded the metabolic balance study, cumulative Na balance was not affected by renal denervation in Sham/CBDL or CHF (INN, 3.71 +/- 0.29 meq; DNX, 3.64 +/- 0.35 meq) was significantly decreased (P < 0.05) in CHF (6.14 +/- 0.85 meq; DNX, 4.67 +/- 0.77 meq). It is concluded that the increased renal Na retention characteristic of cirrhosis and CHF depends partly on increased efferent renal sympathetic nerve activity. This is readily detected during low but not normal dietary Na intake.