Drinking and blood pressure during sodium depletion or ANG II infusion in chronic cholestatic rats

After a chronic ligation of the common bile duct (BDL), Long-Evans rats are hypotensive and have elevated saline intake during both sodium-depleted an d nondepleted conditions. We tested whether BDL rats have exaggerated hypot ension during sodium depletion or an elevated dipsogenic response to angiot ensin II (ANG II) that might help to explain the saline intake. After 4 wk of BDL, rats were hypotensive at baseline and developed exaggerated hypoten sion during acute furosemide-induced diuresis. Without saline to drink, BDL rats increased water intake during depletion equal to sham-ligated rats. H owever, with saline solution available at 22 h after sodium depletion, the BDL rats drank more water and saline than did sham-ligated rats. This rapid intake temporarily increased their mean arterial pressure to equal that of sham-ligated rats. Intravenous infusion of ANG II induced equal drinking r esponses despite reduced presser responses in the BDL rats relative to sham -ligated rats during both ad libitum and sodium-depleted conditions. Thus B DL rats have exaggerated hypotension during diuresis, and their hypotension is corrected by drinking an exaggerated volume of saline, but they do not have an increased drinking response to ANG II.