Haxhiu M A, Erokwu B O, Cherniack N S
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
J Auton Nerv Syst. 1996 Nov 6;61(2):155-61. doi: 10.1016/s0165-1838(96)00076-8.
The respiratory rhythm modulates cholinergic outflow to the tracheal smooth muscle through the parasympathetic nerves. To determine the basis of this modulation, we combined the retrograde tracer technique to identify bulbospinal cells projecting to phrenic motoneurons, and the transneuronal labeling method to visualize medullary neurons that innervate airway-related vagal preganglionic cells. Following injections of fluorogold into the ventral horns of the cervical spinal cord and injections of pseudorabies virus (PRV) into the wall of the extrathoracic trachea of superior cervical ganglioctomized Sprague-Dawley rats. A large number of the double-labeled cells were identified along the ventral aspect of the medulla oblongata. Most frequently, double-labeled neurons were seen in the medial tegmental field, particularly in the parapyramidal region, within the gigantocellular nuclei, and the caudal raphe nuclei. Less frequently, double-labeled neurons were found in the ventrolateral medulla. No double-labeled cell was observed in the dorsal aspect of the medulla oblongata. This study indicates that a subset of medullary neurons that project to phrenic motoneurons also innervate the airway-related vagal preganglionic cells, allowing the coupling of inspiratory activity and parasympathetic outflow to the airways.
呼吸节律通过副交感神经调节气管平滑肌的胆碱能传出。为了确定这种调节的基础，我们结合逆行示踪技术来识别投射到膈运动神经元的延髓脊髓细胞，以及跨神经元标记方法来可视化支配气道相关迷走神经节前细胞的延髓神经元。向上颈神经节切除的Sprague-Dawley大鼠的胸外气管壁注射伪狂犬病病毒（PRV），并向颈脊髓腹角注射荧光金。在延髓腹侧发现了大量双标记细胞。最常见的是，在中脑内侧被盖区，特别是在巨细胞核内的锥体旁区域和尾侧中缝核中观察到双标记神经元。在延髓腹外侧发现双标记神经元的频率较低。在延髓背侧未观察到双标记细胞。这项研究表明，投射到膈运动神经元的一部分延髓神经元也支配气道相关迷走神经节前细胞，从而使吸气活动与气道的副交感神经传出耦合。
