Parkes M J, Lara-Muñoz J P, Izzo P N, Spyer K M
Department of Physiology, Royal Free Hospital School of Medicine, London.
J Physiol. 1994 Apr 1;476(1):131-9.
In anaesthetized rats, extracellular and intracellular recordings were taken from 106 respiratory neurones in the intermediate region of the nucleus ambiguus. We observed unprovoked shortening of expiratory time accompanied, in all classes of respiratory neurone, by the elimination of the changes in membrane potential that were characteristic of stage II expiration. The demonstration of the elimination of stage II expiration in both the rat and cat strongly supports the functional division of expiration into stage I expiration (post-inspiration) and stage II expiration. In order to identify the neurones in the rat that receive inputs from vagal afferents and modulate the central respiratory rhythm, we examined whether any respiratory neurones responded to stimulation of the vagus nerve. Some post-inspiratory and stage II expiratory neurones responded. The short latency (< 2 ms) of four of the responses indicates that some vagal afferents act on post-inspiratory neurones via a disynaptic pathway. While repetitive stimulation of the vagus nerve could inhibit the phrenic rhythm, it appears that most inspiratory neurones in the intermediate region of the nucleus ambiguous complex are not directly involved in integrating the information from vagal afferents with the central respiratory rhythm.
在麻醉大鼠中，从疑核中间区域的106个呼吸神经元进行了细胞外和细胞内记录。我们观察到，在所有类型的呼吸神经元中，呼气时间无端缩短，同时消除了II期呼气特征性的膜电位变化。在大鼠和猫中均证实消除了II期呼气，这有力地支持了将呼气功能分为I期呼气（吸气后）和II期呼气。为了确定大鼠中接受迷走神经传入纤维输入并调节中枢呼吸节律的神经元，我们检查了是否有任何呼吸神经元对迷走神经刺激有反应。一些吸气后和II期呼气神经元有反应。其中四个反应的短潜伏期（<2毫秒）表明，一些迷走神经传入纤维通过双突触途径作用于吸气后神经元。虽然反复刺激迷走神经可抑制膈神经节律，但疑核复合体中间区域的大多数吸气神经元似乎并不直接参与将迷走神经传入纤维的信息与中枢呼吸节律进行整合。
