Renal nerves mediate blunted natriuresis to atrial natriuretic peptide in cirrhotic rats.

The diuretic and natriuretic responses to atrial natriuretic peptide in conscious rats with cirrhosis (chronic bile duct ligation) were examined. Cirrhotic rats had sodium retention, ascites, and elevated liver weights. In conscious control rats, atrial natriuretic peptide increased urine flow rate and urinary sodium excretion. In conscious cirrhotic rats, atrial natriuretic peptide had no effect on urine flow rate or urinary sodium excretion. Renal denervation reversed the blunted diuretic and natriuretic responses to atrial natriuretic peptide in cirrhotic rats. Renal sympathetic nerve activity increased in conscious cirrhotic rats during infusion of atrial natriuretic peptide but decreased in conscious control rats. Inhibition of the renin-angiotensin system with captopril had no effect on the diuretic or natriuretic responses to atrial natriuretic peptide in conscious control or cirrhotic rats. Mean arterial pressure, glomerular filtration rate, and renal plasma flow were affected similarly by atrial natriuretic peptide in control and cirrhotic rats. Increased renal sympathetic nerve activity, but not angiotensin II, mediates the blunted diuretic and natriuretic responses to atrial natriuretic peptide in conscious cirrhotic rats.