Wang Feng-Bin, Liao Yi-Han, Wang Yao-Chen
Department of Psychology, National Chung Cheng University, Chiayi, Taiwan.
Mental Health Promotion Center, National Chung Cheng University, Chiayi, Taiwan.
J Anat. 2017 Feb;230(2):303-314. doi: 10.1111/joa.12560. Epub 2016 Nov 29.
The inner thoracic cavity is lined by the parietal pleura, and the lung lobes are covered by the visceral pleura. The parietal and visceral plurae form the pleural cavity that has negative pressure within to enable normal respiration. The lung tissues are bilaterally innervated by vagal and spinal nerves, including sensory and motor components. This complicated innervation pattern has made it difficult to discern the vagal vs. spinal processes in the pulmonary visceral pleura. With and without vagotomy, we identified vagal nerve fibres and endings distributed extensively in the visceral pleura ('P'-type nerve endings) and triangular ligaments ('L'-type nerve endings) by injecting wheat germ agglutinin-horseradish peroxidase as a tracer into the nucleus of solitary tract or nodose ganglion of male Sprague-Dawley rats. We found the hilar and non-hilar vagal pulmonary pleural innervation pathways. In the hilar pathway, vagal sub-branches enter the hilum and follow the pleural sheet to give off the terminal arborizations. In the non-hilar pathway, vagal sub-branches run caudally along the oesophagus and either directly enter the ventral-middle-mediastinal left lobe or follow the triangular ligaments to enter the left and inferior lobe. Both vagi innervate: (i) the superior, middle and accessory lobes on the ventral surfaces that face the heart; (ii) the dorsal-rostral superior lobe; (iii) the dorsal-caudal left lobe; and (iv) the left triangular ligament. Innervated only by the left vagus is: (i) the ventral-rostral and dorsal-rostral left lobe via the hilar pathway; (ii) the ventral-middle-mediastinal left lobe and the dorsal accessory lobe that face the left lobe via the non-hilar pathway; and (iii) the ventral-rostral inferior lobe that faces the heart. Innervated only by the right vagus, via the non-hilar pathway, is: (i) the inferior (ventral and dorsal) and left (ventral only) lobe in the area near the triangular ligament; (ii) the dorsal-middle-mediastinal left lobe; and (iii) the right triangular ligament. Other regions innervated with unknown vagal pathways include: (i) the middle lobe that faces the superior and inferior lobe; (ii) the rostral-mediastinal inferior lobe that faces the middle lobe; and (iii) the ventral accessory lobe that faces the diaphragm. Our study demonstrated that most areas that face the dorsal thoracic cavity have no vagal innervation, whereas the interlobar and heart-facing areas are bilaterally or unilaterally innervated with a left-rostral vs. right-caudal lateralized innervation pattern. This innervation pattern may account for the fact that the respiratory regulation in rats has a lateralized right-side dominant pattern.
胸腔内侧衬有脏层胸膜，肺叶则被脏胸膜覆盖。脏胸膜和壁胸膜形成胸膜腔，腔内为负压，以保证正常呼吸。肺组织由迷走神经和脊神经双侧支配，包括感觉和运动成分。这种复杂的神经支配模式使得区分肺脏胸膜中的迷走神经与脊神经过程变得困难。通过向雄性Sprague-Dawley大鼠的孤束核或结状神经节注射小麦胚凝集素-辣根过氧化物酶作为示踪剂，我们在有或没有迷走神经切断术的情况下，识别出广泛分布于脏胸膜（“P”型神经末梢）和三角韧带（“L”型神经末梢）中的迷走神经纤维和终末。我们发现了肺门和非肺门迷走神经对肺胸膜的支配途径。在肺门途径中，迷走神经分支进入肺门并沿胸膜片发出终末分支。在非肺门途径中，迷走神经分支沿食管尾侧走行，要么直接进入腹侧中纵隔左叶，要么沿三角韧带进入左叶和下叶。双侧迷走神经支配：（i）面向心脏的腹侧表面的上叶、中叶和副叶；（ii）背侧头端上叶；（iii）背侧尾端左叶；（iv）左三角韧带。仅由左迷走神经支配的是：（i）通过肺门途径的腹侧头端和背侧头端左叶；（ii）通过非肺门途径面向左叶的腹侧中纵隔左叶和背侧副叶；（iii）面向心脏的腹侧头端下叶。仅由右迷走神经通过非肺门途径支配的是：（i）三角韧带附近区域的下叶（腹侧和背侧）和左叶（仅腹侧）；（ii）背侧中纵隔左叶；（iii）右三角韧带。其他由未知迷走神经途径支配的区域包括：（i）面向上叶和下叶的中叶；（ii）面向中叶的头端纵隔下叶；（iii）面向膈肌的腹侧副叶。我们的研究表明，大多数面向胸腔背侧的区域没有迷走神经支配，而叶间区域和面向心脏的区域则由双侧或单侧迷走神经支配，呈现左头端与右尾端的侧化支配模式。这种支配模式可能解释了大鼠呼吸调节具有右侧优势侧化模式这一事实。
