Increased Sympathetic Outflow in Cirrhosis and Ascites: Direct Evidence from Intraneural Recordings

Abstract

This study provides the first direct evidence that elevated plasma norepinephrine concentrations in patients with cirrhosis and ascites are due to increased central sympathetic outflow. Sympathetic nerve activity is not increased in patients with cirrhosis but without ascites. Because there were direct positive correlations of sympathetic nerve activity with plasma norepinephrine concentrations, plasma epinephrine concentrations, plasma renin activity, and heart rate, the increase in central sympathetic outflow in patients with cirrhosis and ascites appears generalized and not restricted to muscle nerves. The anti-natriuretic effects of parallel increases in renal and muscle sympathetic nerve activity could account for the inverse correlation between muscle sympathetic nerve activity and sodium excretion.