Cardiac output during exercise is related to plasma atrial natriuretic peptide but not to central venous pressure in humans

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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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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