Preferential increase in splanchnic sympathetic activity induced by hepatic cirrhosis in rats

Abstract

Increased sympathetic activity and arterial hypotension are found in cirrhotic patients. The aim of this study was to evaluate the control of renal (rSNA) and splanchnic (sSNA) sympathetic nerve activity by the arterial baroreceptors in Wistar rats with cirrhosis induced by bile duct ligation (BDL), experiments were performed four weeks after BDL. Mean arterial pressure (MAP), heart rate (HR), rSNA and sSNA were recorded under anesthesia. The baroreflex sensitivity (BS) was assessed by the reflex changes of rSNA and sSNA induced by alterations in MAP in response to vasoactive drugs. Renal and hepatic noradrenaline was assessed by HPLC. Cirrhotic rats (CR, n=6) showed decreased MAP (control (CO, n=6):108±2 and CR:95±2mmHg) and increased HR (CO:352±10 and CR:396±13bpm). In CR group, significant increase in the basal sSNA (CO:36±8 and CR:115±13pps) accompanied by increased hepatic noradrenaline level (CO:0.7±0.1 and CR:1.4±0.1ng/mL), besides increase in the BS for PHE (CO: −0.47±0.1 and CR: −1.75±0.3) and for SNP (CO: −0.34±0.1 and CR: −1.01±0.2). However, in CR group a significant decrease in rSNA (CO:92±7 and CR:57±5pps) accompanied by no changes in rSNA BS or renal noradrenaline level (0.14±0.1ng/mL). The present study shows that in the initial phase of cirrhosis a preferential increase in sSNA appears independently of arterial baroreceptor dysfunction.Financial support: CAPES and CNPq.