Department of Physiology, University of São Paulo/FMRP, SP, Brazil.
Respir Physiol Neurobiol. 2010 Apr 15;171(1):46-53. doi: 10.1016/j.resp.2010.01.014. Epub 2010 Feb 1.
Central chemoreception, the detection of CO(2)/H(+) within the brain and the resultant effect on ventilation, was initially localized at two areas on the ventrolateral medulla, one rostral (rVLM-Mitchell's) the other caudal (cVLM-Loeschcke's), by surface application of acidic solutions in anesthetized animals. Focal dialysis of a high CO(2)/H(+) artificial cerebrospinal fluid (aCSF) that produced a milder local pH change in unanesthetized rats (like that with a approximately 6.6mm Hg increase in arterial P(CO2)) delineated putative chemoreceptor regions for the rVLM at the retrotrapezoid nucleus and the rostral medullary raphe that function predominantly in wakefulness and sleep, respectively. Here we ask if chemoreception in the cVLM can be detected by mild focal stimulation and if it functions in a state dependent manner. At responsive sites just beneath Loeschcke's area, ventilation was increased by, on average, 17% (P<0.01) only in wakefulness. These data support our hypothesis that central chemoreception is a distributed property with some sites functioning in a state dependent manner.
中枢化学感受性，即对脑内 CO₂/H⁺的检测及其对通气的影响，最初是通过在麻醉动物的延髓腹外侧表面应用酸性溶液来定位在两个区域，一个在腹侧（rVLM-Mitchell），另一个在背侧（cVLM-Loeschcke）。在未麻醉的大鼠中，用高 CO₂/H⁺人工脑脊液（aCSF）进行局部透析，产生了更温和的局部 pH 变化（类似于动脉 PCO₂增加约 6.6mmHg），划定了 rVLM 中的推定化学感受器区域，位于梯形核(retrotrapezoid nucleus)和延髓脑桥背侧的头端，分别在觉醒和睡眠中起主要作用。在这里，我们想问一下 cVLM 中的化学感受性是否可以通过轻度局部刺激来检测，以及它是否以依赖状态的方式起作用。在 Loeschcke 区域下方的反应性部位，通气仅在觉醒时平均增加了 17%（P<0.01）。这些数据支持我们的假设，即中枢化学感受性是一种分布式特性，其中一些部位以依赖状态的方式起作用。
