Boutilier R G, Toews D P
Respir Physiol. 1981 Nov;46(2):161-76. doi: 10.1016/0034-5687(81)90098-0.
The strictly aquatic urodele. Cryptobranchus alleganiensis, is one of the largest gill-less vertebrates in which most of the respiratory gas exchanges occur across the skin. In this study we have examined some of the gas carrying relationships in blood to determine whether certain properties are particularly adaptive to the hellbender's well oxygenated habitat and predominantly cutaneous mode of respiration. The O2 dissociation curve is sigmoidal (n = 2.9) having a P50 of 23.6 mm Hg (at pHa and PaCO2) and a Bohr factor of -0.24. A considerable amount of arterio-venous mixing prior to the ejection of blood from the heart is thought to account for a comparatively low arterial O2 1-1 .pH-1 for a hematocrit of 29%. Attention is drawn to the variability in the protein buffering related CO2 combining properties in vitro caused by hct alterations during different methods of blood sampling. Acid-base relationships between whole blood, true plasma and separated plasma are essentially the same as those described for mammalian blood. Interspecies comparison with the data from this study suggest that factors such as microhabitat, rather than water or air breathing per se, may influence the characteristics of blood O2 and CO2 carriage in amphibians.
严格水生的有尾目动物——隐鳃鲵，是最大的无鳃脊椎动物之一，其大部分呼吸气体交换通过皮肤进行。在本研究中，我们检测了血液中一些气体携带关系，以确定某些特性是否特别适应隐鳃鲵富含氧气的栖息地和主要的皮肤呼吸方式。氧解离曲线呈S形（n = 2.9），P50为23.6毫米汞柱（在pHa和PaCO2条件下），玻尔因子为-0.24。在血液从心脏射出之前，大量动静脉混合被认为是导致血细胞比容为29%时动脉血氧含量相对较低的原因。不同采血方法过程中血细胞比容的变化会导致体外蛋白质缓冲相关二氧化碳结合特性的变异性，这一点值得关注。全血、真血浆和分离血浆之间的酸碱关系与哺乳动物血液中描述的基本相同。与本研究数据的种间比较表明，诸如微生境等因素，而非水呼吸或空气呼吸本身，可能会影响两栖动物血液中氧气和二氧化碳携带的特性。
