Onwochei M O, Snajdar R M, Rapp J P
Department of Medicine, Medical College of Ohio, Toledo 43699.
Am J Physiol. 1987 Nov;253(5 Pt 2):H1044-52. doi: 10.1152/ajpheart.1987.253.5.H1044.
Isolated heart-lung preparations from hypertensive inbred Dahl salt-hypertension sensitive (S) and normotensive inbred Dahl salt-hypertension resistant (R) rats were perfused using 15% washed rat red blood cells in Krebs-Ringer bicarbonate buffer. Atrial pressures were increased by increasing venous return (preload) or by increasing the arterial resistance (afterload). Increases in preload at a constant afterload produced increases in the right and left atrial pressures equivalent between S and R strains. Atrial natriuretic factor (ANF) release was linearly related to right atrial pressure (RAP) or left atrial pressure (LAP) in either strain, but S released more ANF at each level of preload, and the slope of the line relating ANF release to RAP was significantly greater in S than R. When the heart-lung preparations were subjected to changes in afterload at a constant preload, LAP was significantly increased in R but not in S rats, and concomitantly ANF increased in R but not in S. In the afterload experiments, as in the preload studies, S released more ANF than R for comparable LAP. It is concluded that 1) at any atrial pressure, hearts of hypertensive S rats release more ANF than hearts of normotensive R rats, 2) this strain difference is probably a consequence of hypertension, and 3) the observed relationships between ANF release and atrial pressures support the contention that atrial distention stimulates the release of ANF.
使用在 Krebs - Ringer 碳酸氢盐缓冲液中洗涤过的 15%大鼠红细胞，对来自高血压近交系 Dahl 盐敏感型（S）大鼠和正常血压近交系 Dahl 盐抵抗型（R）大鼠的离体心肺标本进行灌注。通过增加静脉回流（前负荷）或增加动脉阻力（后负荷）来升高心房压力。在恒定后负荷下增加前负荷，会使 S 品系和 R 品系的右心房和左心房压力产生同等程度的升高。在任一品系中，心房利钠因子（ANF）的释放与右心房压力（RAP）或左心房压力（LAP）呈线性相关，但在每个前负荷水平下，S 品系释放的 ANF 更多，并且在 S 品系中，ANF 释放与 RAP 的关系曲线斜率显著大于 R 品系。当在恒定前负荷下改变心肺标本的后负荷时，R 品系大鼠的 LAP 显著升高，而 S 品系大鼠则不然，同时，R 品系大鼠的 ANF 增加，S 品系大鼠则未增加。在与前负荷研究类似的后负荷实验中，对于可比的 LAP，S 品系释放的 ANF 比 R 品系更多。得出的结论是：1）在任何心房压力下，高血压 S 品系大鼠的心脏释放的 ANF 比正常血压 R 品系大鼠的心脏更多；2）这种品系差异可能是高血压的结果；3）观察到的 ANF 释放与心房压力之间的关系支持了心房扩张刺激 ANF 释放这一论点。
