University of California, Irvine, Irvine, California 92697.
Integr Comp Biol. 2002 Apr;42(2):208-15. doi: 10.1093/icb/42.2.208.
The functional significance of many features of the reptilian cardiopulmonary system remains unknown; particularly the importance of cardiac shunts. One hypothesis for a physiological function for shunts is that they play a role in myocardial oxygenation and are therefore important when cardiac work is elevated. In this study we examined cardiac function by monitoring electrocardiograms in red-eared slider turtles (Trachemys scripta) with a reduced myocardial oxygen supply. Exposing the animals to a hypoxic gas mixture reduced oxygen levels in the pulmonary venous return. When cardiac work was elevated during hypoxia, the electrocardiogram changed in a manner consistent with myocardial hypoxia, suggesting enrichment of the luminal blood with oxygen by the intracardiac shunt facilitates cardiac performance.
爬行动物心肺系统的许多特征的功能意义仍然未知；特别是心内分流的重要性。心内分流的一个生理功能假说认为，它们在心氧合中起作用，因此在心脏工作量增加时很重要。在这项研究中，我们通过监测红耳龟（Trachemys scripta）的心电图来检查心脏功能，这些动物的心肌供氧减少。使动物暴露在低氧气体混合物中会降低肺静脉回流中的氧气水平。当心脏在低氧时工作量增加时，心电图发生变化，与心肌缺氧一致，这表明心内分流使腔血富氧，从而促进了心脏功能。
