Effect of ANP on circulating blood volume

Abstract

The effects of rat atrial natriuretic peptide (rANP) on blood volume (BV) were determined by the continuous measurement of BV, mean arterial pressure (MAP), and central venous pressure (CVP). Immediately after a single-bolus injection of rANP-(1-28), 1 nmol/100 g body wt, in conscious rats, BV began to decrease. Peak reduction of -0.22 +/- 0.03 ml/100 g body wt was reached 14.5 min after the injection. Thereafter, BV levels returned gradually to -0.08 +/- 0.03 ml/100 g body wt compared with the control value. In volume expansion experiment, the nephrectomized, anesthetized rats were divided into two groups: the control group, with only a saline infusion, and the ANP group, with an infusion of saline with rANP (1 nmol/100 g body wt). In the ANP group, increases in BV were not as great, and recovery was threefold faster than that of the control group. In the ANP group, the recovery time of BV to the starting control levels was 8.5 min, and the time constant of recovery was 3.6 +/- 0.3 min-1. The control group times were 25 min and 11.5 +/- 0.8 min-1, respectively. The effective vascular compliances were approximately 2.8 ml.mmHg-1.kg body wt-1 in both groups, and the capillary filtration coefficient was 0.47 ml.mmHg-1.min-1.kg body wt-1 in the ANP group and 0.33 ml.mmHg-1.min-1.kg body wt-1 in the control group. Thus the whole body capillary filtration coefficient was 1.5-fold higher in the ANP group than in the control group. This suggests that ANP may increase the permeability of capillaries.

Estimation of Filtration Coefficients and Circulating Plasma Volume by Continuously Monitoring Hematocrit during Hemodialysis

“…According to previous studies [8,9] atrial natriuretic peptide (ANP) possibly increases capillary filtration coefficients. Zoccali et al [10] reported that plasma ANP concentration in diabetic uremics on chronic hemodialysis was increased due to autonomic failure, compared with nondiabetic uremics.…”

“…month 9 Lp, ml/ mm Hg/ min 10 Vp0 liters 11 Lp/Vp0 Vp0/BW % 12 1 Cause of renal failure: 1 = diabetic nephropathy; 2 = nondiabetic nephropathy.…”

A Study on Regulating Factors of Plasma Refilling during Hemodialysis

“…In anesthetized rats with bilateral liga tion of both the renal artery and vein, infusion of ANP induces reduction of blood volume and a 1.5-fold increase in the capillary filtration coefficient [10], Almeida et al [11] demonstrated that infusion of ANP for 40 min decreased the plasma volume by 14% in bilaterally nephrcctomized rats. They explained it as the result of efflux of fluid from capillaries.…”

Neurohormonal Systems during Progression of Heart Failure: A Review

“…It is not known how preload is reduced, since ANP does not appear to increase peripheral venous capacitance [26]. The reduction of pulmonary wedge pressure may reflect either an effect on the capillary permeability, with a transloca tion of fluid from the intravascular space to the interstitium, or a direct effect on the myo cardial diastolic relaxation [27]. Further, no significant changes in cardiac output, BP or systemic vascular resistance follows the re duction in preload.…”