Microvascular oxygen transport: impact of a left-shifted dissociation curve.
Microvascular oxygen transport: impact of a left-shifted dissociation curve.
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微血管氧运输：解离曲线左移的影响。
DOI：
10.1152/ajpheart.1992.262.2.h517
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Ellsworth,ML
中科院分区：
文献类型：
--
作者：
Stein,JC;Ellsworth,ML
血红蛋白氧亲和力增加的影响在非缺氧条件下，评价了P50降低对牵开肌毛细血管氧转运的影响（FIo 2 = 0.30和0.21）和缺氧（FIo 2 = 0.10）条件下具有正常氧亲和力的仓鼠[对照; P50 = 26.1 +/- 1.0（SD）mmHg，n = 12]和慢性短期给予氰酸钠诱导的氧亲和力增加的仓鼠[给药; P50 = 16.2 +/- 1.6（SD）mmHg，n = 7]。使用在体内视频显微镜和计算机辅助图像分析，我们确定了氧饱和度（SO2）和相关的血流动力学参数在小动脉（n = 30控制，18治疗）和小静脉（n = 25控制，17治疗）毛细血管。作为对缺氧的反应，对照组动物的全身动脉PO 2降低至29.6 +/- 6.0（SD）mmHg，给药组动物的全身动脉PO 2降低至24.7 +/- 3.8（SD）mmHg，与全身动脉血压突然降低和呼吸频率增加相关。在非低氧通气期间，对照组动物和治疗组动物的毛细血管网络中SO2的减少分别为13.3%和11.0%。在低氧通气期间，对照组动物的SO2降低了9.1%，治疗组动物的SO2降低了8.7%。缺氧时两组血流动力学参数无明显差异。估计的毛细血管末端PO 2在给药动物中显著较低。这些数据表明，增加的氧亲和力并没有提供一个明显的优势，在缺氧期间的毛细血管网络在休息横纹肌的水平氧运输，然而，这样的优势可能会变得明显的存在下，代谢率增加或更严重的缺氧挑战。
The impact of an increased hemoglobin oxygen affinity (decreased P50) on oxygen transport was evaluated in capillaries of the retractor muscle under nonhypoxic (FIo2 = 0.30 and 0.21) and hypoxic (FIo2 = 0.10) conditions in hamsters with normal oxygen affinity [control; P50 = 26.1 +/- 1.0 (SD) mmHg, n = 12] and in hamsters with an increased oxygen affinity [treated; P50 = 16.2 +/- 1.6 (SD) mmHg, n = 7] induced by chronic short-term administration of sodium cyanate. Using in vivo video microscopy and computer-aided image analysis, we determined oxygen saturation (SO2) and associated hemodynamic parameters in both arteriolar (n = 30 control, 18 treated) and venular (n = 25 control, 17 treated) capillaries. In response to hypoxia, systemic arterial PO2 decreased to 29.6 +/- 6.0 (SD) mmHg in control animals and 24.7 +/- 3.8 (SD) mmHg in treated animals associated with abrupt decreases in systemic arterial blood pressure and increases in respiratory rate. The decrease in SO2 across the capillary network during nonhypoxic ventilation was 13.3% SO2 for control animals and 11.0% SO2 for treated animals. During hypoxic ventilation, the decrease in SO2 was 9.1% SO2 in control animals and 8.7% SO2 in treated animals. Hemodynamic parameters were not significantly different in the two groups during hypoxia. Estimated end-capillary PO2 was significantly lower in the treated animals. These data indicate that an increased oxygen affinity does not provide an obvious advantage for oxygen transport during hypoxia at the level of the capillary network in resting striated muscle; however, such an advantage might become apparent in the presence of an increased metabolic rate or a more severe hypoxic challenge.