Control of breathing in vertebrates: effects of chronic respiratory challenges and modulation of discontinuous breathing

这项研究考察了无尾两栖动物(青蛙和蟾蜍)控制呼吸的一些机制。与人类和其他哺乳动物不同，两栖动物不会持续呼吸。相反，他们表现出一种不连续的呼吸模式，称为周期性呼吸。这种类型的呼吸可以是不规则的单次呼吸，偶尔会出现两次呼吸，或将呼吸(通常为4-8次)分成不同的呼吸周期，由称为呼吸暂停的无呼吸周期隔开(可能长达几分钟)。虽然周期性呼吸在两栖动物中是正常的，但在人类中却是异常的和病态的。人类可以在睡眠中表现出这种呼吸模式，要么是由于呼吸道阻塞(阻塞性睡眠呼吸暂停)，要么是由于调节持续呼吸的大脑区域异常(中枢性睡眠呼吸暂停)。人类中任何一种形式的睡眠呼吸暂停都与心脏病发作或中风等心血管疾病风险增加有关。此外，呼吸暂停与血液中氧气水平的降低和血液中二氧化碳水平的增加有关，因为没有持续的呼吸。一般来说，氧气水平的降低被称为缺氧，而二氧化碳水平的增加被称为高碳酸血症。

This research examines some of the mechanisms involved in controlling breathing in anuran amphibians (frogs and toads). Unlike humans and other mammals, amphibians do not breathe continuously. Rather they display a discontinuous pattern of breathing called periodic breathing. This type of breathing can take the form of irregular single breaths, the occasional occurrence of pairs of breaths or the grouping of breaths (usually 4-8) into discrete episodes separated by periods of no breathing called apneas (which can be several minutes in length). While periodic breathing is normal in amphibians, it is abnormal and pathological in humans. Humans can display this pattern of breathing during sleep either due to an obstruction of the airway (obstructive sleep apnoea) or due to abnormalities in the areas of the brain that regulate continuous breathing (central sleep apnoea). Either form of sleep apnoea in humans is associated with increased risk for cardiovascular disease such as heart attack or stroke. Furthermore, apnoea is associated with a reduction in oxygen levels in the blood and an increase in carbon dioxide levels in the blood due to the absence of continuous breathing. In general, a reduction in oxygen levels is called hypoxia while an increase in carbon dioxide levels is called hypercapnia.