Sillau A H, Cueva S, Valenzuela A, Candela E
Respir Physiol. 1976 Aug;27(2):147-55. doi: 10.1016/0034-5687(76)90070-0.
Five male alpacas native to high altitude, of approximately 40 kg, were studied first at 3,300 m and again after a 3-month sojourn at sea level. Measurements were made with the animals standing, unsedated and breathing air. Cardiac output was measured by the dye dilution technique. Blood gas tensions and contents were measured in arterial and mixed venous blood. Blood samples were also equilibrated with different oxygen tensions to construct O2-Hb dissociation curves. The P50 was 17.8 and 19.7 torr at 3,300 m and at sea level, respectively. The higher P50 values at sea level were associated with higher values of base excess. PaO2 was lower at 3,300 m but SaO2 was always above 90%. No significant changes in [Hb], Hct, Q, CaO2 and CvO2 with changes in elevation were observed. PaCO2 tended to be lower at altitude indicating a mild hyperventilation. The values of PvO2 were lower than those reported for other mammals but similar to those of the llama. A higher PvO2 was measured in the alpacas at sea level. The alpaca under conditions of chronic hypoxia presents only minor cardiorespiratory adjustments suggesting the possibility of tissue characteristics well suited for life at high altitude.
对5只原产于高海拔地区、体重约40千克的雄性羊驼进行了研究。首先在海拔3300米处进行研究，然后在海平面停留3个月后再次进行研究。测量时动物站立，未使用镇静剂，呼吸空气。采用染料稀释技术测量心输出量。测量动脉血和混合静脉血中的血气张力和含量。血液样本还与不同的氧张力平衡，以构建氧合血红蛋白解离曲线。在海拔3300米和海平面时，P50分别为17.8和19.7托。海平面时较高的P50值与较高的碱剩余值相关。海拔3300米时动脉血氧分压较低，但动脉血氧饱和度始终高于90%。未观察到血红蛋白浓度、血细胞比容、心输出量、动脉血氧含量和混合静脉血氧含量随海拔变化有显著变化。海拔处动脉血二氧化碳分压往往较低，表明有轻度通气过度。混合静脉血氧分压值低于其他哺乳动物的报道值，但与美洲驼的相似。在海平面的羊驼中测得较高的混合静脉血氧分压。慢性缺氧条件下的羊驼仅表现出轻微的心肺调节，这表明其组织特征可能非常适合在高海拔地区生存。
