Right atrial appendectomy reduces the renal response to acute hypervolemia in the rat

1984 ◽  
Vol 247 (3) ◽  
pp. R610-R613 ◽  
Author(s):  
A. T. Veress ◽  
H. Sonnenberg

We have shown previously that an extract of atrial tissue from rat heart contains a potent natriuretic factor. In this study anesthetized rats were connected to a respirator and the right atrial appendage was either excised, using a loop ligature (experimental group), or the loop was placed around the appendage and then removed (sham-operated group). After equilibration and control urine collection periods an isooncotic Ringers-albumin solution was infused intravenously (25% of estimated blood volume), and renal function was monitored over the next hour. There were no differences between groups in control period arterial or central venous pressures, heart rates, cardiac outputs, renal blood flows, or filtration rates. However, the diuretic and natriuretic responses to infusion in the experimental group were only one half of those in the sham-operated series (vol = 23.4 +/- 6.2 vs. 68.2 +/- 11.0 microliter X min-1 X g kidney wt-1, UNa V = 2,731 +/- 856 vs. 6,504 +/- 962 nmol X min-1 X g kidney wt-1). These differences were not affected by prior bilateral vagotomy. Administration of homologous atrial natriuretic factor or furosemide resulted in identical renal responses in both groups. We conclude therefore that acute hypervolemia is associated with release of atrial natriuretic factor into the bloodstream and that removal of the atrial appendage reduces the amount available for such release.

1995 ◽  
Vol 268 (6) ◽  
pp. R1411-R1417
Author(s):  
D. Javeshghani ◽  
S. Mukaddam-Daher ◽  
L. Fan ◽  
Z. Guan ◽  
J. Gutkowska ◽  
...  

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.


1988 ◽  
Vol 255 (2) ◽  
pp. R232-R236
Author(s):  
D. P. Synhorst ◽  
J. Gutkowska

Interventions that increase atrial pressures in humans or laboratory animals release atrial natriuretic factor (ANF) into the circulation. We studied the relation between distension of the right or left atrium and release of ANF in retrograde-perfused isolated rabbit hearts. A fluid-filled balloon within the right or left atrium was inflated to a mean pressure of 5, 10, 15, or 20 mmHg, and ANF in the cardiac effluent was measured by radioimmunoassay. The slope of the regression line relating ANF release to atrial distending pressure was steeper for the left than right atrium (P less than 0.001), indicating that, at comparable increases in mean pressures, the left atrium releases more ANF than does the right atrium. Left atrial tissue concentration of ANF was greater than right atrial (1.58 +/- 0.15 vs. 1.05 +/- 0.09 micrograms ANF/mg protein, P less than 0.01). In contrast to previous studies showing right atrial dominance in rats, the left atria of isolated, perfused rabbit hearts contain more ANF and release more in response to atrial distension.


2020 ◽  
Vol 21 (6) ◽  
pp. 220-223
Author(s):  
Hiroaki Yamamoto ◽  
Chieko Itamoto ◽  
Minato Hayashi ◽  
Tsunesuke Kohno ◽  
Yu Matsumura ◽  
...  

1991 ◽  
Vol 261 (1) ◽  
pp. H22-H28 ◽  
Author(s):  
K. A. King ◽  
J. R. Ledsome

The effects of tachycardia and a slow (1%/min) 20% reduction and elevation of blood volume (BV) on right atrial pressure (RAP), right atrial dimension (RAD), and plasma immunoreactive atrial natriuretic factor (IR-ANF) were examined in anesthetized rabbits. Plasma IR-ANF was significantly increased during pacing at 6 Hz in the presence of high BV but not at low BV. Mean RAP increased with expansion of BV, but this change was not associated with significant changes in IR-ANF. There were no statistically significant changes in systolic or diastolic RAD with alterations in BV or with tachycardia. Tachycardia had no effect on left atrial dimension. Diastolic right atrial wall stress (DRAS) and minute DRAS increased with a 20% increase in BV, but changes in BV did not affect systolic right atrial wall stress (SRAS) or minute SRAS. Tachycardia decreased DRAS at high BV and significantly increased SRAS and minute SRAS. The increases in SRAS and minute SRAS were greater during tachycardia at high BV, suggesting that an interaction between BV and tachycardia results in potentiation of SRAS and minute SRAS. The results suggest that systolic RAS is a significant factor in ANF release during tachycardia at high BV.


2018 ◽  
Vol 27 ◽  
pp. S317
Author(s):  
M. Morten ◽  
T. Senanayake ◽  
L. Butel-Simões ◽  
N. Mabotuwana ◽  
A. Boyle ◽  
...  

1994 ◽  
Vol 267 (2) ◽  
pp. R380-R386 ◽  
Author(s):  
C. Y. Cheung

Endothelin is a potent vasoconstrictor synthesized by vascular endothelial cells. In the adult, endothelin has been shown to stimulate the release of atrial natriuretic factor (ANF) through a direct action on atrial cardiocytes. The present study was designed to investigate, in the fetus, whether endothelin would similarly release ANF into the circulation. In addition, the effects of endothelin on fetal cardiovascular and urinary functions were explored. Chronically catheterized ovine fetuses between 126 and 139 days gestation (term 147 days) were used for the study. After a 30-min control period, the fetuses were infused intravenously with vehicle (n = 6) or endothelin-1 (n = 9) at 25 ng.min-1.kg-1 for 30 min, and this was followed by a 60-min recovery period. In response to endothelin infusion, plasma ANF levels were significantly elevated. Endothelin infusion acutely increased fetal arterial pressure without affecting venous pressure. Fetal heart rate decreased, and blood volume was reduced. Fetal urine flow rate and urinary excretion of electrolytes did not change during the endothelin infusion but were elevated during the recovery period. The fetus developed hypoxia and acidemia. Thus our study demonstrates that endothelin is effective in stimulating ANF release in the fetus, and this effect appears to be unrelated to the venous pressure changes. In addition, the results suggest that endothelin is a potent vasoconstrictor of the fetal systemic and umbilical vascular beds. The decrease in blood volume and increase in urinary excretion of fluid and electrolytes in response to endothelin are consistent with the known actions of ANF, which is elevated during endothelin infusion.


Sign in / Sign up

Export Citation Format

Share Document