Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
Exp Physiol. 2010 Jun;95(6):657-67. doi: 10.1113/expphysiol.2009.049312. Epub 2010 Apr 1.
The control of breathing depends critically on sensory inputs to the central pattern generator of the brainstem, arising from peripheral arterial chemoreceptors located principally in the carotid bodies (CBs). The CB receptors, i.e. glomus or type I cells, are excited by chemical stimuli in arterial blood, particularly hypoxia, hypercapnia, acidosis and low glucose, which initiate corrective reflex cardiorespiratory and cardiovascular adjustments. Type I cells occur in clusters and are innervated by petrosal afferent fibres. Synaptic specializations (both chemical and electrical) occur between type I cells and petrosal terminals, and between neighbouring type I cells. This, together with the presence of a wide array of neurotransmitters and neuromodulators linked to both ionotropic and metabotropic receptors, allows for a complex modulation of CB sensory output. Studies in several laboratories over the last 20 years have provided much insight into the transduction mechanisms. More recent studies, aided by the development of a co-culture model of the rat CB, have shed light on the role of neurotransmitters and neuromodulators in shaping the afferent response. This review highlights some of these developments, which have contributed to our current understanding of information processing at CB chemoreceptors.
呼吸的控制取决于对脑桥中枢模式发生器的感觉输入的控制，这些输入来自主要位于颈动脉体 (CB) 的外周动脉化学感受器。CB 受体，即球囊或 I 型细胞，被动脉血液中的化学刺激物兴奋，特别是缺氧、高碳酸血症、酸中毒和低血糖，这些刺激物引发纠正性反射性心肺和心血管调节。I 型细胞成群出现，并由岩神经传入纤维支配。I 型细胞和岩神经末梢之间以及相邻的 I 型细胞之间存在突触特化（化学和电）。这一点，加上与离子型和代谢型受体相关的大量神经递质和神经调质的存在，使得 CB 感觉输出的复杂调节成为可能。过去 20 年来，几个实验室的研究为转导机制提供了很多深入的了解。最近的研究，得益于大鼠 CB 共培养模型的发展，阐明了神经递质和神经调质在塑造传入反应中的作用。这篇综述强调了其中的一些发展，这些发展有助于我们当前对 CB 化学感受器信息处理的理解。
