RESPONSE OF RENAL NERVE ACTIVITY TO HIGH NACL FOOD-INTAKE IN DOGS WITH CHRONIC BILE-DUCT LIGATION

Hepatic sensory systems are thought to play an important role in the r esponse of renal nerve activity and natriuresis to oral NaCl load, In this study, responses of renal nerve activity and urinary Na+ and Cl- excretions to a high-NaCl food intake (20 g/kg boiled rice containing 0.4 g/kg NaCl) were examined in sham-operated dogs (n = 12) and dogs w ith chronic bile duct ligation (CBDL; n = 10). In sham-operated dogs, renal nerve activity gradually decreased and reached minimal value (50 % +/- 7% of the control value) at 100 minutes after the high-NaCl food intake and remained depressed until 4 hours after the food intake. Of the orally administered sodium and chloride, 27% +/- 5% and 23% +/- 6 % were excreted over the following 4 hours, respectively, In CBDL dogs , the decrease in renal nerve activity induced by the high-NaCl food w as completely abolished and only 4% +/- 1% of the loaded Na+ and 3% +/ - 2% of the loaded Cl- were excreted, Furthermore, liver tissue norepi nephrine concentration in CBDL dogs decreased to 21% of that of sham-o perated dogs, These results suggest that (1) In CBDL dogs, the decreas e in renal nerve activity induced by a high-NaCl food is completely ab olished, probably because of the impairment of hepatic neural regulati on, (2) The lack of renal nerve response may contribute, at least in p art, to the abnormalities in body fluid homeostasis in cirrhosis.