Pressure diuresis and autonomic function in conscious dogs

Brand, Paul H.; Coyne, KS; Kostrzewski, K. A.; Shier, David N.; Metting, Patricia J.; Britton, Steven L.

doi:10.1152/ajpregu.1991.261.4.r802

Cited by 7 publications

(7 citation statements)

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“…Consistent with previous animal studies [17,18], we demonstrated a significant linear correlation between MAP and tissue perfusion. The severity of hypotension after IVC clamp placement predicts the degree of intestinal edema and the reduction in renal perfusion resulting in decreased urine output.…”

Section: Discussionsupporting

confidence: 92%

Partial IVC Clamping Improves Intraoperative Hemodynamic Parameters in the Rodent Portacaval Anastomosis Model

Asgeri¹,

Waghray²,

Mullen³

et al. 2011

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The mechanisms involved in the development of hepatic encephalopathy still remain uncertain. The rodent portacaval shunt is a model that reproduces many of the pathological features observed in humans (1), but is a technically demanding exercise. While the traditional technique involves complete occlusion of the IVC, a c-clamp was fashioned to partially clamp the IVC thereby sustaining venous return and cardiac output. The aim of this study is to determine if the c-clamp technique provides greater hemodynamic stability and enhances the success rate of the portacaval shunt procedure. To answer this question, two experimental groups, c-clamp (N = 7) and cross-clamp (N = 7), and a sham group (N = 3) were included. Intraoperative hemodynamic parameters were recorded at specific times during the procedure. The c-clamp group showed greater hemodynamic stability when compared to the cross-clamp group. It was manifested by 1) significantly higher mean arterial blood pressure [63 (range, 8) vs 47 (range, 10) mmHg, p < 0.05], 2) faster capillary refill [4 (range, 2) vs 6 (range, 2) seconds, p < 0.05], 3) higher urinary output [0.18 (range, 0.02) vs 0.14 (range, 0.02) ml, p < 0.05], and 4) lower bowel wet-to-dry ratio [4.168 (range, 0.258) vs 4.731 (range, 0.271), p<0.05]. We conclude partial IVC clamping improves hemodynamic stability during the construction of the rat portacaval shunt model

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Section: Discussionsupporting

confidence: 92%

Partial IVC Clamping Improves Intraoperative Hemodynamic Parameters in the Rodent Portacaval Anastomosis Model

Asgeri¹,

Waghray²,

Mullen³

et al. 2011

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“…The increase in renal vascular resistance is likely to limit the extent to which changes in AP are transmitted to the renal interstitium in anaesthetized animals. In contrast, in the conscious animal, normal activity influences neural control of renal blood flow (Grady & Bullivant, 1992) and the interaction of the pressure diuresis mechanism with the autonomic nervous system (Brand, Coyne, Kostrzewski, Shier, Metting & Britton, 1991). Additionally, in conscious animals, AP fluctuates considerably even in the resting state (Trapani, Barron & Brody, 1986;Alper, Jacob & Brody, 1987;DeBoer, Karemaker & Strackee, 1987).…”

Section: Discussionmentioning

confidence: 98%

Spontaneous changes in arterial blood pressure and renal interstitial hydrostatic pressure in conscious rats.

Skarlatos

Brand

Metting

et al. 1994

The Journal of Physiology

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1. Previous work has demonstrated a positive relationship between experimentally induced changes in arterial pressure (AP) and renal interstitial hydrostatic pressure (RIHP). The purpose of the present study was to test the hypothesis that RIHP is positively correlated with the normal changes in AP that occur spontaneously in conscious rats. 2. Rats were chronically instrumented for the recording of AP (via an aortic catheter) and RIHP. RIHP was measured by implanting a Millar microtransducer, whose tip had been encapsulated in a 35 ,um pore polyethylene matrix (5 mm long, 2 mm o.d.), approximately 5 mm below the renal cortical surface. 3. A total of 56 h of simultaneous analog recording of AP and RIHP was obtained from ten rats. Each 1 h segment was digitized and evaluated at frequencies of 1, 0-1, 0-02 and 0O01 Hz. 4. In forty-nine out of fifty-six of these 1 h recordings taken at 1 Hz, there were significant positive linear correlations between AP and RIHP (mean r = 0 32) with a mean slope of 0-11 mmHg RIHP/1 mmHg AP. Low-pass filtering to 0 01 Hz significantly increased the r value to 0-48. 5. These results demonstrate that spontaneous changes in AP and RIHP are positively correlated. The spontaneous coupling of AP and RIHP may be of importance in the regulation of salt and water excretion by the pressure diuresis mechanism.Both theory and experimental evidence indicate that a close correspondence between arterial pressure (AP) and urinary excretion of salt and water (pressure diuresis) is

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“…The extent to which the pressure diuresis mechanism is masked by other mechanisms may be estimated by comparing the slope of the isolated, intrinsic pressure diuresis mechanism to the slope of the relationship between arterial pressure and urine flow in the intact, conscious animal. We previously estimated that the slope of the isolated pressure diuresis mechanism in the rat kidney is 100 times greater than the slope of the arterial pressure‐urine flow relationship in the conscious dog (9, 13). In the present study, the slope of the arterial pressure‐urine flow relationship in intact rats on a high‐salt diet was 0.00025 ml/mmHg.…”

Section: Discussionmentioning

confidence: 39%

“…In conscious dogs, Brand et al . (13) demonstrated that changes in arterial pressure induced by behavioral arousal were correlated short‐term with directionally similar changes in urine flow. Nafz et al .…”

Section: Discussionmentioning

confidence: 97%

“…However, in the intact organism, pressure diuresis acts in concert with all the other mechanisms that restore sodium balance in response to changes in dietary sodium content. Thus the activity of the pressure diuresis mechanism in the intact organism is masked by changes, for example, in autonomic activity (13) that may act on the kidney both via influencing renal hemodynamics and via changes in renin secretion. Therefore, in the intact organism, the expression of pressure diuresis might be expected to be state‐dependent.…”

mentioning

confidence: 99%

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State‐Dependent Expression of Pressure Diuresis in Conscious Rats

Steele

Koch

Brand

2000

Proc Soc Exp Biol Med

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Abstract. In 1967, Guyton and Coleman modeled pressure diuresis as the underlying, essential, long‐term mechanism that regulates arterial pressure when sodium intake changes. Other mechanisms that influence renal function interact with pressure diuresis to achieve sodium balance and determine the blood pressure. Increases in sodium intake suppress sodium conserving mechanisms and activate natriuretic mechanisms; decreases in sodium intake have the opposite effect. If the Guyton‐Coleman model is correct, then pressure diuresis should be more readily detected in animals on a high‐salt diet than in animals on a low‐salt diet. We measured spontaneous changes in arterial pressure and urine flow in conscious rats fed low‐salt (0.4% NaCl) and high‐salt (8.0% NaCl) chow. For 10 rats fed a high‐salt diet, arterial pressure and urine flow were positively correlated in 19 of 32 (59%) trials. In 10 rats fed a low‐salt diet, a positive correlation was observed in 10 of 33 (30%) trials. Chi‐square analysis revealed that differences in Na+ content of the diet were significantly associated with the probability of a positive relationship between blood pressure and urine flow. These results support the hypothesis that the expression of pressure diuresis across time is dependent on the state of sodium balance.

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Pressure diuresis and autonomic function in conscious dogs

Cited by 7 publications

References 0 publications

Partial IVC Clamping Improves Intraoperative Hemodynamic Parameters in the Rodent Portacaval Anastomosis Model

Partial IVC Clamping Improves Intraoperative Hemodynamic Parameters in the Rodent Portacaval Anastomosis Model

Spontaneous changes in arterial blood pressure and renal interstitial hydrostatic pressure in conscious rats.

State‐Dependent Expression of Pressure Diuresis in Conscious Rats

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