León-Velarde Fabiola, Richalet Jean-Paul
Universidad Peruana Cayetano Heredia, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencius Filosafia, Laboratorio de Transporte de Oxígeno, Lima, Perú.
High Alt Med Biol. 2006 Summer;7(2):125-37. doi: 10.1089/ham.2006.7.125.
Highland population (HA) from the Andes, living above 3000 m, have a blunted ventilatory response to increasing hypoxia, breathe less compared to acclimatized newcomers, but more, compared to sea-level natives at sea level. Subjects with chronic mountain sickness (CMS) breathe like sea-level natives and have excessive erythrocytosis (EE). The respiratory stimulation that arises through the peripheral chemoreflex is modestly less in the CMS group when compared with the HA group at the same P(ET(O2)). With regard to CO(2) sensitivity, CMS subjects seem to have reset their central CO(2) chemoreceptors to operate around the sea-level resting P(ET(CO2)). Acetazolamide, an acidifying drug that increases the chemosensitivity of regions in the brain stem that contain CO(2)/H(+) sensitive neurons, partially reverses this phenomenon, thus, providing CMS subjects with the possibility to have high CO(2) changes, despite small changes in ventilation. However, the same type of adjustments of the breathing pattern established for Andeans has not been found necessarily in Asian humans and/or domestic animals nor in the various high altitude species studied. The differing time frames of exposure to hypoxia among the populations, as well as the reversibility of the different components of the respiratory process at sea level, provide key concepts concerning the importance of time at high altitude in the evolution of an appropriate breathing pattern.
来自安第斯山脉海拔3000米以上地区的高原人群（HA）对缺氧增加的通气反应减弱，与适应环境的新来者相比呼吸较少，但与海平面的海平面本地人相比呼吸较多。患有慢性高山病（CMS）的受试者呼吸方式与海平面本地人相似，并有红细胞增多症（EE）。在相同的呼气末氧分压（P(ET(O2))）下，与HA组相比，CMS组通过外周化学反射产生的呼吸刺激略少。关于二氧化碳敏感性，CMS受试者似乎已重置其中枢二氧化碳化学感受器，使其在海平面静息呼气末二氧化碳分压（P(ET(CO2))）附近发挥作用。乙酰唑胺是一种酸化药物，可增加脑干中含有二氧化碳/氢离子敏感神经元区域的化学敏感性，部分逆转这种现象，因此，尽管通气变化很小，仍使CMS受试者有可能出现高二氧化碳变化。然而，在亚洲人类和/或家畜以及所研究的各种高海拔物种中，不一定能发现为安第斯人建立的相同类型的呼吸模式调整。人群中缺氧暴露的不同时间框架，以及海平面呼吸过程不同组成部分的可逆性，提供了关于高海拔时间在适当呼吸模式演变中的重要性的关键概念。
