Daly M de B, Cook M N, Sykes R M, Spyer K M
Department of Physiology, Royal Free and University College Medical School, London, UK.
Auton Neurosci. 2001 Jun 20;89(1-2):60-73. doi: 10.1016/s1566-0702(01)00255-7.
The functional distribution of uncrossed and crossed pulmonary afferent fibres in the cervical vagus nerves has been studied in the anaesthetized cat using acute and chronic unilateral pneumonectomized preparations. The heart and lungs were sympathectomized routinely. The vagal afferent pathways of three pulmonary reflexes were investigated: the Hering-Breuer respiratory reflex, the lung inflation cardio-accelerator reflex, and the pulmonary chemoreflex. Inflation of the remaining lung caused temporary inhibition of inspiration. It also resulted in acceleration of the heart, but only when the background cardiac vagal tone was augmented. These respiratory and cardiac responses were abolished in most animals by ipsilateral cervical vagotomy; however, in some, a small response persisted and this was abolished by contralateral vagotomy. Stimulation of pulmonary C-fibre endings with right atrial injections of phenylbiguanide caused a reduction in respiration, bradycardia and systemic hypotension, responses which occurred with a latency of 2.9 +/- 0.15 s. They were mostly abolished by ipsilateral cervical vagotomy, but reduced responses persisted in a few animals. The residual responses were abolished by contralateral cervical vagotomy and by selective denervation of the lung. These results indicate that most afferent fibres subserving the three pulmonary reflexes studied run in the ipsilateral cervical vagus, representing the uncrossed pathway. Some afferent fibres, however, cross to the contralateral cervical vagus. Degenerative changes in cells of the contralateral nodose ganglion in chronic unilateral pneumonectomized animals support these findings.
利用急性和慢性单侧肺切除的麻醉猫制备物，研究了颈迷走神经中未交叉和交叉的肺传入纤维的功能分布。心脏和肺常规进行交感神经切除。研究了三种肺反射的迷走传入途径：黑林-布雷尔呼吸反射、肺充气心脏加速反射和肺化学反射。对剩余肺进行充气导致吸气暂时抑制。它还导致心脏加速，但仅在背景心脏迷走神经张力增强时出现。在大多数动物中，同侧颈迷走神经切断术消除了这些呼吸和心脏反应；然而，在一些动物中，仍有小的反应持续存在，而对侧迷走神经切断术消除了这种反应。通过右心房注射苯乙双胍刺激肺C纤维末梢导致呼吸减弱、心动过缓和全身低血压，这些反应的潜伏期为2.9±0.15秒。它们大多通过同侧颈迷走神经切断术消除，但在少数动物中仍有减弱的反应持续存在。残余反应通过对侧颈迷走神经切断术和肺的选择性去神经支配而消除。这些结果表明，参与所研究的三种肺反射的大多数传入纤维走行于同侧颈迷走神经，代表未交叉的途径。然而，一些传入纤维交叉至对侧颈迷走神经。慢性单侧肺切除动物对侧结节神经节细胞的退行性变化支持了这些发现。
