Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO2 : role of carotid body CO2.
Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO2 : role of carotid body CO2.
复制标题
外周化学感受器决定中枢化学感受器对 CO2 的呼吸敏感性：颈动脉体 CO2 的作用。
DOI：
10.1113/jp270114
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Dempsey,JeromeA
中科院分区：
文献类型：
--
作者：
Smith,CurtisA;Blain,GrégoryM;Henderson,KathleenS;Dempsey,JeromeA
7只清醒犬，体外灌流分离的颈动脉小体(CB)，观察其对中枢化学感受器对全身性高碳酸血症通气性的影响，证实CB循环与脑循环分离。当分离的CB为高碳酸血症时。低碳酸血症和当分离的CB为正常二氧化碳时。低碳酸血症时，平均每分钟通气量的中枢CO2反应斜率(P≤)和平均吸气流速(VT/TI)显著增加(P<0.0 5)。7只狗中有6只的潮气量(VT)、呼吸频率(FB)和横隔膜肌电上升速率增加，但无统计学意义。我们认为，在完整动物安静清醒的条件下，在大范围的CB和CB中，高加性是化学感受器相互作用的主要形式。在7只清醒犬血管隔离和体外灌流CBS模型上，观察了CB常氧低碳酸血症、常碳酸血症和高碳酸血症(颈动脉体分别为22、41和68≈)对中枢化学感受器通气性二氧化碳敏感性的影响。一种CB对化疗的敏感性与完整犬相似。在4只CB失神经的狗身上，CB灌流19-75毫米汞柱时没有高/低呼吸反应，证实了灌流的CB循环与脑分离。当CB为高碳酸血症时，平均中心CO2反应斜率在每分钟通气量增加303%(P≤)(P<0.01)，平均吸气流速(VT/TI)增加251%(P≤<0.05)。7只动物中有6只动物的潮气量(VT)、呼吸频率(FB)和横隔肌电信号上升速率的中枢性CO2反应斜率增加，但组内均值变化无统计学意义。当CB正常时，组平均中心CO2反应斜率增加237%(P≤=0.01)，VT/TI增加249%(P≤=0.05)。低碳酸血症与高碳酸血症患者的中枢呼吸机反应指数无显著差异。我们认为，当化学感觉控制系统完整，反应获得生理性反应，颈动脉小体化学感受器受大范围的O2和/或CO2驱动时，高加性是安静觉醒中化学感受器相互作用的主要形式。
Key PointsThe influence of specific carotid body (CB) normoxic hypocapnia, hypercapnia and normocapnia on the ventilatory sensitivity of central chemoreceptors to systemic hypercapnia was assessed in seven awake dogs with extracorporeal perfusion of the vascularly isolated CB.Chemosensitivity in this preparation was similar to that in the intact animal.Separation of CB circulation from that of the brain was confirmed.When the isolated CB was hypercapnicvs. hypocapnic and when the isolated CB was normocapnicvs. hypocapnic, the group mean central CO2response slopes of minute ventilation () (P≤ 0.01) and mean inspiratory flow rate (VT/TI) (P≤ 0.05) increased significantly. Tidal volume (VT), breathing frequency (fb)and rate of rise of diaphragm EMG were increased in 6 of 7 dogs but did not achieve statistical significance.We propose that hyperaddition is the dominant form of chemoreceptor interaction under conditions of quiet wakefulness in intact animals and over a wide range of CB and .AbstractWe asked if the type of carotid body (CB) chemoreceptor stimulus influenced the ventilatory gain of the central chemoreceptors to CO2. The effect of CB normoxic hypocapnia, normocapnia and hypercapnia (carotid body ≈ 22, 41 and 68 mmHg, respectively) on the ventilatory CO2sensitivity of central chemoreceptors was studied in seven awake dogs with vascularly‐isolated and extracorporeally‐perfused CBs. Chemosensitivity with one CB was similar to that in intact dogs. In four CB‐denervated dogs, absence of hyper‐/hypoventilatory responses to CB perfusion with of 19–75 mmHg confirmed separation of the perfused CB circulation from the brain. The group mean central CO2response slopes were increased 303% for minute ventilation ()(P≤ 0.01) and 251% for mean inspiratory flow rate (VT/TI) (P≤ 0.05) when the CB was hypercapnicvs. hypocapnic; central CO2response slopes for tidal volume (VT), breathing frequency (fb) and rate of rise of the diaphragm EMG increased in 6 of 7 animals but the group mean changes did not reach statistical significance. Group mean central CO2response slopes were also increased 237% for (P≤ 0.01) and 249% forVT/TI(P≤ 0.05) when the CB was normocapnicvs. hypocapnic, but no significant differences in any of the central ventilatory response indices were found between CB normocapnia and hypercapnia. These hyperadditive effects of CB hyper‐/hypocapnia agree with previous findings using CB hyper‐/hypoxia.We propose that hyperaddition is the dominant form of chemoreceptor interaction in quiet wakefulness when the chemosensory control system is intact, response gains physiological, and carotid body chemoreceptors are driven by a wide range of O2and/or CO2.