Parkes M J
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
National Institute for Health Research/Wellcome Trust Birmingham Clinical Research Facility, University Hospitals Birmingham National Health Service Foundation Trust, Birmingham, B15 2TH, UK.
Exp Physiol. 2017 Dec 1;102(12):1567-1583. doi: 10.1113/EP086561. Epub 2017 Oct 19.
What is the topic of this review? One of the major unanswered questions in physiology is that of how breathing matches metabolic rate. Venous chemoreceptors seem to have been dismissed since the 1960s. What advances does it highlight? New evidence shows that their apparent dismissal needs reappraisal. The paper on which this depends has more than one interpretation, and another paper obtained the opposite result. Previous search ignored all locations between skeletal muscle and the right heart. Oxygen sensors other than the arterial chemoreceptors do exist. Heymans and colleagues originally demonstrated some residual breathing response to hypoxia in sino-aortically denervated animals. Similar results occur in humans. One of the major unanswered questions in physiology is that of how breathing matches metabolic rate. The existence in humans of venous chemoreceptors that might control breathing seems to have been dismissed since the 1960s. New evidence has emerged showing that this apparent dismissal needs reappraisal. First, the paper in humans on which this depends has more than one interpretation. Moreover, a previous paper obtained the opposite result and is not cited. Secondly, previous search for venous chemoreceptors failed to examine all venous locations between skeletal muscle and the right heart and lungs. Thirdly, oxygen sensors other than the arterial chemoreceptors do exist. Heymans himself originally demonstrated some residual breathing response to hypoxia in sino-aortically denervated animals. Others confirm a residual breathing response to hypoxia in mammals, including humans. There is now considerable interest in the importance of afferent feedback in controlling the cardiovascular and respiratory systems. Moreover, it is now clear that arterial, aortic and central chemoreceptors have no role in explaining how breathing matches metabolic rate during exercise. These together provide a timely reminder that venous chemoreceptors remain ideal candidates still to be considered as metabolic rate sensors to explain matching in humans. Firstly, this is because venous PO2 and PCO2 values do change appropriately in proportion to metabolic rate, so a metabolic rate signal sufficient to drive breathing might already exist. Secondly, chemoreceptor-like anatomical structures are present in the systemic venous system but remain unexplored. Finally, no extant experimental evidence precludes their existence.
这篇综述的主题是什么？生理学中一个主要的未解决问题是呼吸如何与代谢率相匹配。自20世纪60年代以来，静脉化学感受器似乎已被摒弃。它突出了哪些进展？新证据表明，它们被明显摒弃的情况需要重新评估。其所依据的论文有不止一种解释，而另一篇论文得到了相反的结果。之前的研究忽略了骨骼肌与右心之间的所有部位。除了动脉化学感受器之外，确实存在其他氧传感器。海曼斯及其同事最初证明，在经窦主动脉去神经支配的动物中，对低氧存在一些残余呼吸反应。人类也有类似结果。生理学中一个主要的未解决问题是呼吸如何与代谢率相匹配。自20世纪60年代以来，人类中可能控制呼吸的静脉化学感受器的存在似乎已被摒弃。新证据表明，这种明显的摒弃需要重新评估。首先，其所依据的关于人类的论文有不止一种解释。此外，之前的一篇论文得到了相反的结果却未被引用。其次，之前对静脉化学感受器的研究未能检查骨骼肌与右心及肺之间的所有静脉部位。第三，除了动脉化学感受器之外，确实存在其他氧传感器。海曼斯本人最初证明，在经窦主动脉去神经支配的动物中，对低氧存在一些残余呼吸反应。其他人证实，包括人类在内的哺乳动物对低氧存在残余呼吸反应。目前，人们对传入反馈在控制心血管和呼吸系统中的重要性有相当大的兴趣。此外，现在很清楚，动脉、主动脉和中枢化学感受器在解释运动期间呼吸如何与代谢率相匹配方面没有作用。这些共同适时地提醒人们，静脉化学感受器仍然是理想的候选者，仍有待被视为代谢率传感器来解释人类中的匹配情况。首先，这是因为静脉血氧分压和二氧化碳分压值确实会随着代谢率的变化而适当地改变，所以可能已经存在足以驱动呼吸的代谢率信号。其次，在体循环静脉系统中存在类似化学感受器的解剖结构，但仍未被探索。最后，现有的实验证据并不排除它们的存在。
