Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO2
Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO2
复制标题
DOI：
10.1113/jphysiol.2010.187211
复制
发表时间：
2010-07-01
影响因子：
5.5
通讯作者：
Dempsey, Jerome A.
中科院分区：
文献类型：
--
作者：
Blain, Gregory M.;Smith, Curtis A.;Dempsey, Jerome A.
我们在8只未麻醉清醒的狗中评估了颈动脉体化学感受器对特定CNS高碳酸血症的缓解反应的贡献。我们去神经支配一个颈动脉体（CB），并对可逆性分离的剩余CB进行体外血液灌注，以维持正常CB血气（含氧量正常，碳酸含量正常的灌流液），以抑制（高氧、低碳酸灌注液）或刺激（低氧、碳酸正常的灌注液）CB化学感受器反射，而体循环，因此CNS和中枢化学感受器，连续暴露于四个渐进水平的全身动脉高碳酸血症，通过增加吸入CO2的分数，在每个水平持续7分钟。单侧CB去神经支配和CB灌注本身都不影响呼吸。相对于CB对照条件（常氧、常碳酸灌注），我们发现CB化学反射抑制降低了所有犬对CNS高碳酸血症的缓解反应的斜率，平均为对照值的19%（范围0-38%; n = 6），而CB化学反射刺激增加了所有犬对CNS高碳酸血症的缓解反应的斜率，平均为对照值的223（范围204-235%; n = 4）。我们的结论是，在狗的中枢神经系统CO2/H+化学感受器的增益是严重依赖于CB传入活动和CNS-CB相互作用的结果在hyperadditive的澄清反应，以中央高碳酸血症。
We assessed the contribution of carotid body chemoreceptors to the ventilatory response to specific CNS hypercapnia in eight unanaesthetized, awake dogs. We denervated one carotid body (CB) and used extracorporeal blood perfusion of the reversibly isolated remaining CB to maintain normal CB blood gases (normoxic, normocapnic perfusate), to inhibit (hyperoxic, hypocapnic perfusate) or to stimulate (hypoxic, normocapnic perfusate) the CB chemoreflex, while the systemic circulation, and therefore the CNS and central chemoreceptors, were exposed consecutively to four progressive levels of systemic arterial hypercapnia via increased fractional inspired CO2 for 7 min at each level. Neither unilateral CB denervation nor CB perfusion, per se, affected breathing. Relative to CB control conditions (normoxic, normocapnic perfusion), we found that CB chemoreflex inhibition decreased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 19% of control values (range 0-38%; n = 6), whereas CB chemoreflex stimulation increased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 223% of control values (range 204-235%; n = 4). We conclude that the gain of the CNS CO2/H+ chemoreceptors in dogs is critically dependent on CB afferent activity and that CNS-CB interaction results in hyperadditive ventilatory responses to central hypercapnia.