Delacourt C, Canet E, Praud J P, Bureau M A
Jeremy Rill Center, Département de Pédiatrie, Université de Sherbrooke, Québec, Canada.
Respir Physiol. 1995 Jan;99(1):29-39. doi: 10.1016/0034-5687(94)00078-e.
The effect of vagal afferents on the ventilatory response to hypoxia was studied in eleven awake newborn lambs. Tests were repeated before and after vagotomy in the same lambs in two conditions: with intact upper airways and after intubation. During hypoxia, a diphasic pattern of ventilatory response was observed in both vagotomized and intact lambs. However, face mask-breathing vagotomized lambs had a blunted increase in ventilation (VI) to hypoxia as compared with intact lambs (P = 0.0001) and they showed an expiratory braking during all hypoxic time. Furthermore, the normal increase in frequency (f) to hypoxia was abolished after vagotomy. After intubation, expiratory braking disappeared and, consequently, magnitude of the VI response to hypoxia was similar in intact and vagotomized lambs. These changes were due to improved tidal volume response in vagotomized intubated lambs (P < 0.002) with no significant change in f response. We concluded that, in awake newborn lambs, vagal afferents are essential for maintaining the pattern and the magnitude of the ventilatory response to hypoxia, the latter by controlling the motor output to the larynx.
在11只清醒的新生羔羊中研究了迷走神经传入对低氧通气反应的影响。在相同的两只羔羊身上，分别在上呼吸道完整和插管两种情况下，于迷走神经切断术前和术后重复进行测试。在低氧期间，迷走神经切断的羔羊和未切断的羔羊均观察到双相通气反应模式。然而，与未切断迷走神经的羔羊相比，面罩呼吸的迷走神经切断羔羊对低氧的通气量（VI）增加减弱（P = 0.0001），并且在所有低氧时间段均出现呼气制动。此外，迷走神经切断后，对低氧的正常频率（f）增加消失。插管后，呼气制动消失，因此，未切断迷走神经和迷走神经切断的羔羊对低氧的VI反应幅度相似。这些变化是由于迷走神经切断的插管羔羊潮气量反应改善（P < 0.002），而f反应无显著变化。我们得出结论，在清醒的新生羔羊中，迷走神经传入对于维持低氧通气反应的模式和幅度至关重要，后者通过控制喉部的运动输出实现。
