Maginniss L A, Kilgore D L
Division of Biology and Medicine, Brown University, Providence, RI 02912.
Respir Physiol. 1989 May;76(2):205-14. doi: 10.1016/0034-5687(89)90098-4.
Isocapnic O2 equilibrium curves (O2ECs) were generated for whole blood of 4 adult burrowing owls (Athene cunicularia) using thin film techniques. At in vivo pHa (7.49 +/- 0.02; mean +/- 1 SEM) and 41 degrees C, the PO2 at half saturation (P50) was 42.3 +/- 0.8 Torr. CO2 and fixed acid (H+) Bohr slopes (delta log P50/delta pH) were -0.46 +/- 0.01 and -0.42 +/- 0.02, respectively, demonstrating a small specific CO2 effect. CO2 and H+ Bohr slopes were saturation-independent between 0.1 and 0.9 S. Hill plots for Athene blood were non-linear; the Hill coefficient (n) increased from 2.6 below 0.4 S to 3.4 above 0.6 S. Owl equilibrium data were accurately described by the equation: S = [(7.7 x 10(6]/(P4 + 44P3 - 108P2 + 3.5 x 10(4)P) + 1]-1. This complex O2EC shape may result from Hb heterogeneity; isoelectric focusing showed 4 isoHbs with a molar ratio of 9:1:1:1. This study revealed no apparent adaptations of Athene blood for hypoxic and hypercapnic conditions. We conclude that the observed blood O2 binding properties promote tissue O2 delivery during periods of surface activity. While occupying its burrow, the owl compensates for moderate alterations in inspired gas composition partly through increased ventilation.
使用薄膜技术生成了4只成年穴小鸮（穴小鸮属）全血的等碳酸氧平衡曲线（O2ECs）。在体内pHa（7.49±0.02；平均值±1个标准误）和41℃时，半饱和氧分压（P50）为42.3±0.8托。二氧化碳和固定酸（H+）的波尔斜率（δlog P50/δpH）分别为-0.46±0.01和-0.42±0.02，表明存在较小的特异性二氧化碳效应。二氧化碳和H+的波尔斜率在0.1至0.9饱和度（S）之间与饱和度无关。穴小鸮血液的希尔图呈非线性；希尔系数（n）从低于0.4 S时的2.6增加到高于0.6 S时的3.4。穴小鸮的平衡数据可由以下方程准确描述：S = [（7.7×10⁶）/（P⁴ + 44P³ - 108P² + 3.5×10⁴P） + 1]⁻¹。这种复杂的O2EC形状可能源于血红蛋白（Hb）的异质性；等电聚焦显示有4种等血红蛋白，摩尔比为9:1:1:1。本研究未发现穴小鸮血液对低氧和高碳酸血症条件有明显适应性。我们得出结论，观察到的血液氧结合特性在表面活动期间促进了组织氧输送。当穴小鸮占据其洞穴时，它部分通过增加通气来补偿吸入气体成分的适度变化。
