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Total and renal sympathetic nervous system activity in alcoholic cirrhosis
Abstract:
Basal sympathetic nervous system activity was assessed in 8 unmedicated patients with alcoholic cirrhosis using a previously developed radiotracer method for measuring total and renal noradrenaline release to, and clearance from, plasma. Compared to the control group total noradrenaline clearance was significantly increased in the patients with advanced alcoholic cirrhosis (Pugh grade C) [1.89 +/- 0.13 vs 1.51 +/- 0.11 l/min, P less than 0.05) indicating that endogenous plasma noradrenaline levels underestimate total sympathetic nervous system activity in these patients. Renal noradrenaline clearance was similar to controls independent of the severity of the liver disease. Both total and renal noradrenaline release were significantly increased in the patients with cirrhosis. The ratio of renal to total noradrenaline release was similar in cirrhotic (26 +/- 7%) and control (23 +/- 5%) groups. Increased arterial plasma adrenaline levels, indicative of adrenal medullary stimulation, were also evident in the patients with cirrhosis and correlated significantly with total noradrenaline spillover (r = 0.732, P less than 0.05). These results strongly suggest that in patients with cirrhosis, rather than a preferential increase in renal sympathetic tone, the increase is part of a pattern of generalized sympathoadrenomedullary activation. Although renal renin secretion was significantly increased in the cirrhotic group no correlation with renal noradrenaline release was seen (r = 0.199), raising the possibility that in cirrhosis renal sympathetic tone is not a major determinant of renal renin secretion. Finally, renal noradrenaline release did not correlate with renal blood or plasma flow but an influence of the sympathetic nervous system on renal function was suggested by the correlation observed between total noradrenaline spillover and impaired salt (r = -0.683, P less than 0.05) and water excretion (r = -0.702, P less than 0.05) demonstrated in the cirrhotic patients.