Daristotle L, Berssenbrugge A D, Engwall M J, Bisgard G E
Department of Comparative Biosciences, University of Wisconsin, Madison 53706.
Respir Physiol. 1990 Feb;79(2):123-35. doi: 10.1016/0034-5687(90)90012-n.
This study was designed to examine the influence of carotid body (CB) hypocapnia on ventilation by selectively perfusing the CB through an extracorporeal circuit in 19 goats. When PcbCO2 was decreased from normocapnic levels in 14 awake goats (delta PcbCO2 = 10.9 Torr), PaCO2 increased 5.6 Torr (P less than 0.05) and VE decreased 24% (P less than 0.001) (mean values). The ventilatory sensitivity to inspired CO2 was not changed by CB hypocapnia in 5 of these goats, but the response was shifted to the right. During CB hypocapnia, ventilatory instability, including apnea, was observed in 4 of 14 goats; this irregular breathing continued at elevated levels of PaCO2. In 5 anesthetized goats, CB hypocapnia (delta PcbCO2 = 18.0 Torr) decreased VE by 70% in the intact state, but produced no significant ventilatory depression after CB denervation. We conclude that CB hypocapnia depresses ventilation in both awake and anesthetized goats mostly through CB chemoreceptor effects, and suggest that this hypoventilation may predispose to ventilatory instability in some animals.
本研究旨在通过体外循环选择性灌注19只山羊的颈动脉体（CB），来检测CB低碳酸血症对通气的影响。在14只清醒山羊中，当PcbCO2从正常碳酸水平降低时（ΔPcbCO2 = 10.9托），动脉血二氧化碳分压（PaCO2）升高5.6托（P < 0.05），每分通气量（VE）降低24%（P < 0.001）（平均值）。在其中5只山羊中，CB低碳酸血症并未改变对吸入二氧化碳的通气敏感性，但反应向右偏移。在CB低碳酸血症期间，14只山羊中有4只出现通气不稳定，包括呼吸暂停；这种不规则呼吸在PaCO2升高时仍持续存在。在5只麻醉山羊中，CB低碳酸血症（ΔPcbCO2 = 18.0托）在完整状态下使VE降低70%，但在CB去神经支配后未产生显著的通气抑制。我们得出结论，CB低碳酸血症主要通过CB化学感受器效应抑制清醒和麻醉山羊的通气，并表明这种通气不足可能使一些动物易发生通气不稳定。
