Denjean A, Canet E, Praud J P, Gaultier C, Bureau M
Laboratoire de Physiologie INSERM CJF 8909, Hôpital A. Béclère, Clamart, France.
Respir Physiol. 1991 Feb;83(2):201-10. doi: 10.1016/0034-5687(91)90029-i.
Hypoxia enhances bronchial responsiveness in sheep and dogs and we recently reported a similar effect in asthmatic subjects. Activation of a reflex arc due to stimulation of peripheral chemoreceptors has been suggested to explain this finding. We evaluated the contribution of carotid body chemoreceptors to hypoxia-induced bronchial responsiveness in conscious sheep. Incremental concentrations of aerosolized methacholine were given to each of seven sheep ventilated successively (in a random order) with a normoxic and a hypoxic gas mixture (15% O2 in N2), both before and after peripheral surgical chemodenervation. Hypoxia alone did not affect lung mechanics in intact or chemodenervated animals. Bronchial responsiveness to methacholine was significantly increased by hypoxia in intact sheep, as compared to chemodenervated sheep. We conclude that hypoxia has a stimulating effect on bronchial responsiveness in awake sheep similar to that seen in human patients with asthma. This increased responsiveness may be mediated by hypoxic stimulation of carotid body chemoreceptors, which in turn may influence the nervous control of airway calibre.
缺氧会增强绵羊和狗的支气管反应性，我们最近报道在哮喘患者中也有类似效应。有人提出，外周化学感受器受刺激引发反射弧的激活可解释这一发现。我们评估了清醒绵羊中颈动脉体化学感受器对缺氧诱导的支气管反应性的作用。在对七只绵羊进行外周手术化学去神经支配前后，分别用常氧和低氧混合气体（氮气中含15%氧气）依次（随机顺序）对每只绵羊进行雾化乙酰甲胆碱递增浓度给药。单独缺氧对完整或化学去神经支配的动物的肺力学没有影响。与化学去神经支配的绵羊相比，完整绵羊中缺氧显著增加了对乙酰甲胆碱的支气管反应性。我们得出结论，缺氧对清醒绵羊的支气管反应性有刺激作用，类似于在哮喘患者中观察到的情况。这种反应性增加可能由颈动脉体化学感受器的缺氧刺激介导，进而可能影响气道口径的神经控制。
