Retrotrapezoid nucleus: a litmus test for the identification of central chemoreceptors
Retrotrapezoid nucleus: a litmus test for the identification of central chemoreceptors
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DOI：
10.1111/j.1469-445x.2005.t01-1-00134.x
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发表时间：
2005-05-01
影响因子：
2.7
通讯作者：
Mulkey, DK
中科院分区：
文献类型：
--
作者：
Guyenet, PG;Stornetta, RL;Mulkey, DK
中枢化学感受是中枢神经系统检测动脉血P-CO2以调节呼吸的机制。有两种主要的理论被提出来解释这一现象。分布式化学敏感性理论认为，pH敏感性是脑干神经元的一个普遍属性，中枢化学感受性是pH对无数神经元的累积效应的结果。特化化学感受器理论设想存在小而特化的CNS细胞群（化学感受器），其独特的能力是检测非常小的pH值波动，并通过特定的连接，调节本身对pH无反应的呼吸网络。最近发现的后斜方核（RTN）的CO2敏感神经元似乎具有人们所期望的这种化学感受器的大多数属性。在这篇综述中，我们还提出，在体内髓神经元对CO（2）的内在反应比先前体外实验中预期的要少得多。RTN神经元的特性为20世纪60年代早期提出的中枢化学感受的专门化学感受器理论提供了新的支持。然而，仍然存在许多不确定性，特别是关于化学感受的分子机制，实际检测体内pH值的细胞类型（神经元，神经胶质或其他）以及真正的中央化学感受器的数量和位置。
Central chemoreception is the mechanism by which arterial blood P-CO2 is detected by the CNS to regulate breathing. Two main theories have been proposed to account for the phenomenon. The distributed chemosensitivity theory argues that pH sensitivity is a widespread attribute of brainstem neurones and that central chemoreception results from the cumulative effects of pH on countless neurones. The specialized chemoreceptor theory envisions the existence of small and specialized populations of CNS cells (chemoreceptors) that are unique in their ability to detect very small pH fluctuations and, via specific connections, regulate a respiratory network that is itself unresponsive to pH. The recently identified CO2-sensitive neurones of the retrotrapezoid nucleus (RTN) seem to possess most of the attributes that one would expect of such chemoreceptors. In this review we also suggest that many fewer medullary neurones are intrinsically responsive to CO(2)in vivo than might have been anticipated from prior experimentation in vitro. The properties of RTN neurones provide renewed support for the specialized chemoreceptor theory of central chemoreception, proposed in the early 1960s. However, many uncertainties remain, especially as regards the molecular mechanisms of chemoreception, the type of cell that actually detects pH in vivo (neurone, glia or others) and the number and location of bona fide central chemoreceptors.