Nattie E
Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756-0001, USA.
Respir Physiol. 2000 Sep;122(2-3):223-35. doi: 10.1016/s0034-5687(00)00161-4.
Central chemoreceptors appear to be widely distributed in the brainstem. Why are there so many central chemoreceptor sites? This review focuses on two hypotheses. (1) The high sensitivity of the respiratory control system as a whole to small changes in systemic P(CO(2)) results from an additive, or greater, effect of the multiple central chemoreceptor sites. Each site provides a fraction of the total response and, importantly, provides tonic excitatory input in eucapnia as well. (2) Individual central chemoreceptor sites vary in effectiveness depending on the arousal or vigilance state of the animal. For example, some sites are more important in wakefulness; others in sleep. Proof for these hypotheses depends critically on obtaining accurate measures of stimulus intensity at each chemoreceptor site in vivo.
中枢化学感受器似乎广泛分布于脑干。为何会有如此多的中枢化学感受器位点呢？本综述聚焦于两种假说。（1）整个呼吸控制系统对全身P(CO₂)的微小变化具有高敏感性，这源于多个中枢化学感受器位点的累加效应或更强效应。每个位点提供总反应的一部分，并且重要的是，在正常碳酸血症时也提供紧张性兴奋性输入。（2）单个中枢化学感受器位点的有效性因动物的觉醒或警觉状态而异。例如，一些位点在清醒时更重要；另一些在睡眠时更重要。这些假说的证据关键取决于在体内获得每个化学感受器位点刺激强度的准确测量值。
