Ma Amy, Bravo Milo, Kappagoda C Tissa
Division of Cardiovascular Medicine, University of California, Davis, One Shield's Avenue, TB 172, Davis, CA 95616, USA.
Respir Physiol Neurobiol. 2003 Nov 14;138(2-3):155-63. doi: 10.1016/s1569-9048(03)00189-7.
Rapidly adapting receptors (RAR) in the lung are stimulated when the lung compliance is reduced. The present investigation was undertaken to determine whether bronchial C-fibers are also activated when lung compliance is decreased since both RAR and bronchial C-fibers are influenced by extra-vascular fluid in the airways. Action potentials (AP) were recorded from bronchial C, pulmonary C, RAR and slowly adapting receptor (SAR) afferents in the cervical vagus in open chest New Zealand White rabbits ventilated at a constant rate and tidal volume. AP were recorded during (a) positive end-expiratory pressure (PEEP) of 2-3 cmH2O (control), (b) zero end-expiratory pressure (ZEEP), (c) negative end-expiratory pressure (NEEP) of -4 cmH2O, (d) restoration of PEEP and (e) final control after hyper-inflation. Both RAR and bronchial C-fiber activity increased significantly compared with control when lung compliance was decreased (bronchial C-fibers: 35 +/- 5 vs. 66 +/- 13 impulses per 30 sec and RAR: 3 +/- 1 vs. 94 +/- 14 impulses per 30 sec).
当肺顺应性降低时，肺内的快速适应感受器（RAR）会受到刺激。由于RAR和支气管C纤维都受到气道内血管外液体的影响，因此本研究旨在确定当肺顺应性降低时支气管C纤维是否也会被激活。在开胸的新西兰白兔中，以恒定的速率和潮气量进行通气，记录颈迷走神经中支气管C纤维、肺C纤维、RAR和慢适应感受器（SAR）传入纤维的动作电位（AP）。在以下情况下记录AP：（a）呼气末正压（PEEP）为2-3 cmH2O（对照），（b）呼气末零压（ZEEP），（c）呼气末负压（NEEP）为-4 cmH2O，（d）恢复PEEP，以及（e）过度充气后的最终对照。当肺顺应性降低时，与对照相比，RAR和支气管C纤维的活动均显著增加（支气管C纤维：每30秒35±5次与66±13次冲动，RAR：每30秒3±1次与94±14次冲动）。
