Wood S C
Oxygen Transport Program, Lovelace Medical Foundation, Albuquerque, New Mexico 87108.
Annu Rev Physiol. 1991;53:71-85. doi: 10.1146/annurev.ph.53.030191.000443.
Hypoxic animals have an impressive arsenal of defense mechanisms, many of which are common to other kind of stresses. Physiologic defense mechanisms, e.g. increasing cardiac output or ventilation, are effective but also energy demanding. An alternative to improving O2 supply is reduction of O2 demand. This is easily accomplished by ectothermic vertebrates by seeking a cooler environment and augmenting the rate of cooling by increased perfusion of the skin. More surprising is that endotherms respond to hypoxia in the same way. Unlike near drowning, where the hypothermia is forced (but still effective), the behavioral hypothermia appears to be regulated and analogous to fever. Much more work is needed in this formative area of research to establish mechanisms, functional significance, and pathways common to stresses other than hypoxia.
缺氧动物拥有一系列令人印象深刻的防御机制，其中许多与其他类型的应激反应相同。生理防御机制，如增加心输出量或通气量，虽然有效，但也需要能量。改善氧气供应的另一种方法是减少氧气需求。变温脊椎动物通过寻找较凉爽的环境并通过增加皮肤灌注来提高散热速率，很容易做到这一点。更令人惊讶的是，恒温动物对缺氧的反应也是如此。与近乎溺水时被迫出现体温过低（但仍然有效）不同，行为性体温过低似乎是受调节的，并且类似于发热。在这个研究的形成阶段，需要做更多的工作来建立缺氧以外应激反应的机制、功能意义和共同途径。
