Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
J Comp Neurol. 2010 Oct 1;518(19):3883-906. doi: 10.1002/cne.22435.
By definition central respiratory chemoreceptors (CRCs) are cells that are sensitive to changes in brain PCO(2) or pH and contribute to the stimulation of breathing elicited by hypercapnia or metabolic acidosis. CO(2) most likely works by lowering pH. The pertinent proton receptors have not been identified and may be ion channels. CRCs are probably neurons but may also include acid-sensitive glia and vascular cells that communicate with neurons via paracrine mechanisms. Retrotrapezoid nucleus (RTN) neurons are the most completely characterized CRCs. Their high sensitivity to CO(2) in vivo presumably relies on their intrinsic acid sensitivity, excitatory inputs from the carotid bodies and brain regions such as raphe and hypothalamus, and facilitating influences from neighboring astrocytes. RTN neurons are necessary for the respiratory network to respond to CO(2) during the perinatal period and under anesthesia. In conscious adults, RTN neurons contribute to an unknown degree to the pH-dependent regulation of breathing rate, inspiratory, and expiratory activity. The abnormal prenatal development of RTN neurons probably contributes to the congenital central hypoventilation syndrome. Other CRCs presumably exist, but the supportive evidence is less complete. The proposed locations of these CRCs are the medullary raphe, the nucleus tractus solitarius, the ventrolateral medulla, the fastigial nucleus, and the hypothalamus. Several wake-promoting systems (serotonergic and catecholaminergic neurons, orexinergic neurons) are also putative CRCs. Their contribution to central respiratory chemoreception may be behavior dependent or vary according to the state of vigilance.
根据定义，中枢呼吸化学感受器（CRCs）是对脑 PCO2或 pH 变化敏感的细胞，有助于对高碳酸血症或代谢性酸中毒引起的呼吸刺激。CO2可能通过降低 pH 起作用。相关的质子受体尚未确定，可能是离子通道。CRCs 可能是神经元，但也可能包括对酸敏感的神经胶质细胞和血管细胞，它们通过旁分泌机制与神经元进行通讯。Retrotrapezoid 核（RTN）神经元是最完全特征化的 CRCs。它们对 CO2的高敏感性在体内可能依赖于其内在的酸敏感性、颈动脉体和脑区（如中缝核和下丘脑）的兴奋性输入，以及来自相邻星形胶质细胞的促进作用。RTN 神经元是呼吸网络在围产期和麻醉状态下对 CO2作出反应所必需的。在清醒的成年人中，RTN 神经元对 pH 依赖性呼吸频率、吸气和呼气活动的调节贡献程度未知。RTN 神经元的异常产前发育可能导致先天性中枢性通气不足综合征。其他 CRCs 可能存在，但支持证据不太完整。这些 CRCs 的拟议位置是延髓中缝核、孤束核、腹外侧延髓、小脑顶核和下丘脑。几个觉醒促进系统（5-羟色胺能和儿茶酚胺能神经元、食欲素能神经元）也是推定的 CRCs。它们对中枢呼吸化学感受的贡献可能依赖于行为或根据警觉状态而变化。
