Action of endogenous atrial natriuretic peptide in calves with experimental acute central venous congestion and low cardiac output

The purpose of this study was to determine whether high plasma levels of atrial natriuretic peptide (ANP) in compensated heart failure are important in the maintenance of sodium balance. This was achieved by subjecting eight dogs to bilateral atrial appendectomy (APX) to blunt the ANP response to pacing-induced heart failure. Five intact dogs served as controls. In controls, 14 days of left ventricular pacing at 240 beats/min produced a sustained fall in cardiac output and mean arterial pressure of approximately 40 and 20%, respectively; compared with cardiac output, reductions in renal blood flow (up to approximately 25%) were less pronounced and even smaller decrements in GFR occurred (up to 9%). Despite these changes and a threefold elevation in plasma norepinephrine concentration, plasma renin activity (PRA) did not increase and sodium balance was achieved during the second week of pacing in association with a six- to eightfold rise in plasma levels of ANP. Similar responses occurred in four dogs in which APX was relatively ineffective in blunting the ANP response to pacing. In marked contrast, there were substantial increments in PRA and in plasma norepinephrine concentration, and marked sodium and water retention during the last week of pacing in four dogs with APX and severely deficient ANP. These results indicate that ANP plays a critical role in promoting sodium excretion in the early stages of cardiac dysfunction.

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Atrial natriuretic peptide increases resistance to venous return in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1987.252.5.h894 ◽

1987 ◽

Vol 252 (5) ◽

pp. H894-H899 ◽

Cited By ~ 4

Author(s):

Y. W. Chien ◽

E. D. Frohlich ◽

N. C. Trippodo

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Arterial Pressure ◽

Atrial Natriuretic Peptide ◽

Natriuretic Peptide ◽

Total Peripheral Resistance ◽

Venous Return ◽

Venous Pressure ◽

Peripheral Resistance ◽

Atrial Natriuretic

To examine mechanisms by which administration of atrial natriuretic peptide (ANP) decreases venous return, we compared the hemodynamic effects of ANP (0.5 microgram X min-1 X kg-1), furosemide (FU, 10 micrograms X min-1 X kg-1), and hexamethonium (HEX, 0.5 mg X min-1 X kg-1) with those of vehicle (VE) in anesthetized rats. Compared with VE, ANP reduced mean arterial pressure (106 +/- 4 vs. 92 +/- 3 mmHg; P less than 0.05), central venous pressure (0.3 +/- 0.3 vs. -0.7 +/- 0.2 mmHg; P less than 0.01), and cardiac index (215 +/- 12 vs. 174 +/- 10 ml X min-1 X kg-1; P less than 0.05) and increased calculated resistance to venous return (32 +/- 3 vs. 42 +/- 2 mmHg X ml-1 X min X g; P less than 0.01). Mean circulatory filling pressure, distribution of blood flow between splanchnic organs and skeletal muscles, and total peripheral resistance remained unchanged. FU increased urine output similar to that of ANP, yet produced no hemodynamic changes, dissociating diuresis, and decreased cardiac output. HEX lowered arterial pressure through a reduction in total peripheral resistance without altering cardiac output or resistance to venous return. The results confirm previous findings that ANP decreases cardiac output through a reduction in venous return and suggest that this results partly from increased resistance to venous return and not from venodilation or redistribution of blood flow.

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Mechanism for decrease in cardiac output with atrial natriuretic peptide in dogs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1989.256.3.h760 ◽

1989 ◽

Vol 256 (3) ◽

pp. H760-H765 ◽

Cited By ~ 8

Author(s):

R. W. Lee ◽

S. Goldman

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Atrial Natriuretic Peptide ◽

Natriuretic Peptide ◽

Blood Volume ◽

Left Ventricular ◽

Right Atrial ◽

Total Blood Volume ◽

Total Blood ◽

Atrial Natriuretic

To examine the mechanism by which atrial natriuretic peptide (ANP) decreases cardiac output, we studied changes in the heart, peripheral circulation, and blood flow distribution in eight dogs. ANP was given as a bolus (3.0 micrograms/kg) followed by an infusion of 0.3 microgram.kg-1.min-1. ANP did not change heart rate, total peripheral vascular resistance, and the first derivative of left ventricular pressure but decreased mean aortic pressure from 91 +/- 4 to 76 +/- 3 mmHg (P less than 0.001) and cardiac output from 153 +/- 15 to 130 +/- 9 ml.kg-1.min-1 (P less than 0.02). Right atrial pressure and left ventricular end-diastolic pressure also decreased. Mean circulatory filling pressure decreased from 7.1 +/- 0.3 to 6.0 +/- 0.3 mmHg (P less than 0.001), but venous compliance and unstressed vascular volume did not change. Resistance to venous return increased from 0.056 +/- 0.008 to 0.063 +/- 0.010 mmHg.ml-1.kg.min (P less than 0.05). Arterial compliance increased from 0.060 +/- 0.003 to 0.072 +/- 0.004 ml.mmHg-1.kg-1 (P less than 0.02). Total blood volume and central blood volume decreased from 82.2 +/- 3.1 to 76.2 +/- 4.6 and from 19.8 +/- 0.8 to 17.6 +/- 0.6 ml/kg (P less than 0.02), respectively. Blood flow increased to the kidneys. We conclude that ANP decreases cardiac output by decreasing total blood volume. This results in a lower operating pressure and volume in the venous capacitance system with no significant venodilating effects. Cardiac factors and a redistribution of flow to the splanchnic organs are not important mechanisms to explain the decrease in cardiac output with ANP.

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Atrial natriuretic peptide in pregnant and lactating goats

Acta Endocrinologica ◽

10.1530/acta.0.1200519 ◽

1989 ◽

Vol 120 (4) ◽

pp. 519-525 ◽

Cited By ~ 23

Author(s):

K. Olsson ◽

B. E. Karlberg ◽

L. Eriksson

Keyword(s):

Atrial Natriuretic Peptide ◽

Natriuretic Peptide ◽

Venous Pressure ◽

Control Period ◽

Plasma Concentrations ◽

Central Venous ◽

Lactating Goats ◽

Pregnancy And Lactation ◽

And Control ◽

Atrial Natriuretic

Abstract. Plasma concentrations of atrial natriuretic peptide (ANP) were measured in 6 goats during pregnancy, lactation and a nonpregnant, nonlactating (= control) period before and during a rapid iv load of 0.9% NaCl. The volume of the load was 20% of blood volume. The infusions increased central venous pressure by 7 ± 1 mmHg during pregnancy and 8 ± 1 mmHg during lactation. Before infusions plasma ANP concentrations were 5.7 ± 0.7 pmol/l (control period), 10.8 ± 1.8 pmol/l (pregnancy;P< 0.05),and6.5 ± 1.5 pmol/l (lactation;NS).ANP increased significantly in all periods. Maximal values were 12.5 ± 1.5 (control period), 25.5 ± 2.3 (pregnancy; P< 0.01 vs control period, P<0.05 vs lactation), and 13.0 ± 1.6 (lactation; NS). Renal Na excretion increased similarly during pregnancy and control period, but slightly more during lactation. In 4 of the goats iv infusions of ANP (1 μg/min, 60 min) were given. The infusions caused natriuresis during the control period, but not during pregnancy and lactation, despite more than 10-fold increases of plasma ANP levels. In conclusion, our results indicate that although plasma ANP concentration rose to high levels during acute NaCl loading in pregnant goats, this effect was not important for the natriuresis. Instead, the natriuretic response to ANP appears attenuated during pregnancy, and also during lactation.

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