Congestive heart failure in rats is associated with increased collecting duct vasopressin sensitivity and vasopressin type 2-receptor re-externalization.

Congestive heart failure in rats is associated with increased collecting duct vasopressin sensitivity and vasopressin type 2-receptor re-externalization. Am J Physiol Renal Physiol. 2013 Oct 2; Authors: Brønd L, Müllertz KM, Torp M, Nielsen J, Græbe M, Hadrup N, Nielsen S, Christensen S, Jonassen TE Abstract A number of studies have shown that rats with congestive heart failure (CHF) have increased protein levels of the vasopressin-regulated water channel AQP2 even during conditions with unchanged circulating levels of vasopressin (AVP), suggesting an increase in the sensitivity of the AVP type-2 (V2) receptor in experimental CHF. The present study was aimed at investigating AVP signaling in rats with moderate CHF (left ventricular end diastolic pressure >10 mmHg; normal plasma AVP levels) induced by ligation of the left anterior descending coronary artery. Sham-operated rats were used as controls. Western blotting analyses revealed an increased abundance of AQP2 in renal cortex (+ 33±9 % of Sham; p<0.05) and in inner medulla (IM) (+54±15% of Sham; p<0.05) in CHF rats when compared to sham operated controls. Dose response studies on isolated collecting ducts (CD's) showed an increased accumulation of cAMP in response to AVP in CHF rats when compared to controls. V2-receptor surface binding studies in isolated IMCD's showed a marked and comparable AVP-induced V2-receptor internalization in response to AVP in both CHF and control r...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research