Thirst in the rat after ligation of the inferior vena cava: Role of angiotensin II

Influence of Salt Intake, ANG II Synthesis and SFO Lesion on Thirst and Blood Pressure During Sodium Depletion

“…Furthermore, the highest mean BUN values observed in the captopril-injected groups (19±3 mg/dl) were only slightly higher than the expected normal range as defined by the kit (5-17 mg/dl). For reference, rats subjected to five-sixths nephrectomy had mean BUN levels of 25 and 84 mg/dl when maintained on low and high protein diets, respectively (Jarusiripipat et al, 1991), and rats subjected to cava ligation above the renal veins for 1 day had a 10-fold increase in plasma urea concentration as measured by a spectrophotometric urease method (Mann et al, 1981). Thus, rats in the present conditions did not appear to be uremic, even though they may have been anuric.…”

“…These arguments have been countered by Mann et al (1981) and Evered et al, (1989) with respect to the effects of the blocking treatments on plasma ANG II levels and blood pressure. Fitts (1994) replicated a failure to prevent isoproterenolinduced thirst with high doses of blockers in the brain ventricles (Lee et al, 1981), but further demonstrated that much lower doses of blocker did effectively block the drinking if the infusions were made directly into the SFO.…”

“…Depletion with a sodium deficient diet requires several days, and rapid models of thirst are more commonly used, such as administration of vasodilators, dialysis or interference with the circulation (Fitts, 1994;Gardiner & Stricker, 1985;Lind et al, 1984;Mann et al, 1981;Simpson et al, 1978;Stricker 1977Stricker , 1978. Animals can be depleted rapidly with diuretics, and the acute water intake after such treatments has been studied.…”

Current animal models for the study of congestion in heart failure: an overview

“…In this way, the CVP increases above the upper limit of normal (> 8 mmHg), thereby inducing venous congestion in a similar way as seen in patients [2]. Tying a surgical wire [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]; inserting a metal clamp [59,60], adjustable band [61][62][63][64], or constrictor cuff around the IVC [65,66]; or placing an inflatable balloon via the femoral vein [49,53,[67][68][69] are frequently used techniques to constrict the IVC. As a result, CVP varied between 11 to 15 mmHg below the constriction while the CVP above the constriction remained unchanged [44,65].…”

“…Third, often a local and no systemic congestion was induced, when the abdominal IVC was constricted at the level of the renal or hepatic veins [43,47,48,50,51,[54][55][56][57][58]68], in contrast to patients in which the abdomen's entire venous system is congested, potentially explaining contradicting results in animal models versus clinical trials. Fourth, the chronic phase of congestion-weeks to months-was not investigated as the constriction was only maintained for hours to days, or the animals were only often studied for a few days [44][45][46][47][48][49][50][51][52][53][54][55][56][58][59][60][61][62][63][64][65][66][67][68][69]. Finally, the effect of constriction on abdominal organ function, besides the kidneys, was not investigated [47,51,54,58,[61][62][63][64][67]…”