Klinger J R, Pietras L, Warburton R, Hill N S
Division of Pulmonary, Sleep, and Critical Care Medicine, Rhode Island Hospital and Brown University School of Medicine, Providence, RI 02903, USA.
Exp Biol Med (Maywood). 2001 Oct;226(9):847-53. doi: 10.1177/153537020122600907.
To test the hypothesis that reduced oxygen tension stimulates cardiac atrial natriuretic peptide (ANP) secretion, we measured ANP release and expression in neonatal rat atrial and ventricular cardiac myocytes exposed to 45 min and 3, 6, and 24 hr of 3% or 21% oxygen. In atrial cardiocytes, the percentage of increase in culture media ANP concentration from baseline was greater in cells exposed to 3% than in cells exposed to 21% oxygen after 3 hr (814% +/- 52% vs. 567% +/- 33%, P < 0.05) and 6 hr of exposure (1639% +/- 91% vs. 1155% +/- 73%, P < 0.05). No differences in the percentage of increase in culture media ANP concentration was seen at 45 min (284% +/- 27% vs. 201% +/- 16%, P = NS) or 24 hr (2499% +/- 250% vs. 2426% +/- 195%). There was a significant increase in cellular ANP content between 3 and 24 hr in atrial cardiocytes exposed to 21% oxygen (105% +/- 40% vs. 296% +/- 60%, P < 0.05), but not in atrial cardiocytes exposed to 3% oxygen (118% +/- 20% vs. 180% +/- 26%, P = NS). Steady-state ANP mRNA levels in atrial cardiocytes were not affected by oxygen tension. In ventricular cardiocytes, oxygen tension did not affect ANP secretion, cellular ANP content, or steady-state ANP mRNA levels. We conclude that reduced oxygen tension increases release of ANP from atrial, but not ventricular cardiocytes and that this mechanism may contribute to the elevation in plasma ANP seen during acute hypoxia.
为了验证低氧张力刺激心钠素（ANP）分泌这一假说，我们测定了暴露于3%或21%氧气环境中45分钟以及3、6和24小时的新生大鼠心房和心室心肌细胞中ANP的释放及表达情况。在心房心肌细胞中，培养介质中ANP浓度相对于基线的增加百分比，在暴露于3%氧气3小时后（814%±52%对567%±33%，P<0.05）和6小时后（1639%±91%对1155%±73%，P<0.05），暴露于3%氧气的细胞高于暴露于21%氧气的细胞。在45分钟（284%±27%对201%±16%，P=无显著差异）或24小时（2499%±250%对2426%±195%）时，培养介质中ANP浓度增加百分比未见差异。暴露于21%氧气的心房心肌细胞在3至24小时期间细胞内ANP含量显著增加（105%±40%对296%±60%，P<0.05），但暴露于3%氧气的心房心肌细胞则未增加（118%±20%对180%±26%，P=无显著差异）。心房心肌细胞中ANP的稳态mRNA水平不受氧张力影响。在心室心肌细胞中，氧张力不影响ANP分泌、细胞内ANP含量或ANP稳态mRNA水平。我们得出结论，低氧张力增加心房而非心室心肌细胞中ANP的释放，并且这一机制可能导致急性缺氧期间血浆ANP升高。
