Hahn H L, Graf P D, Nadel J A
J Appl Physiol. 1976 Oct;41(4):581-9. doi: 10.1152/jappl.1976.41.4.581.
In 18 open-chest dogs we obtained pressure-diameter (P-D) curves from tantalum bronchograms and pressure-volume (P-V) curves by plethysmography. After vagotomy most of the decrease in diameter with decreasing transpulmonary pressure (Ptp) occured below 10 cmH2O and there was no P-D hysteresis. Smaller airways narrowed more with decreasing Ptp than larger ones. Bronchodilators did not increase diameters after vagotomy (P less than 0.2). With vagi intact, diameters were smaller at all Ptp (P less than 0.01) and exhibited hysteresis, but the lung P-V curve was unchanged. Vagal stimulation narrowed airways further at all Ptp and hysteresis was marked. Smaller airways narrowed more with vagal stimulation than larger ones. Vagal stimulation did not change the deflation limb of the P-V curve but decreased inflation volumes slightly at all Ptp (P less than 0.01). We conclude that in vivo tone is vagal and that it affects the physical properties of airways, but not of lungs, making the airways remarkably independent from lung parenchyma.
在18只开胸犬身上，我们通过钽支气管造影获得了压力-直径（P-D）曲线，并通过体积描记法获得了压力-容积（P-V）曲线。迷走神经切断术后，随着跨肺压（Ptp）降低，大部分直径减小发生在10 cmH2O以下，且不存在P-D滞后现象。随着Ptp降低，较小气道比较大气道狭窄更明显。迷走神经切断术后支气管扩张剂未增加气道直径（P<0.2）。迷走神经完整时，在所有Ptp下气道直径均较小（P<0.01）且呈现滞后现象，但肺P-V曲线未改变。迷走神经刺激在所有Ptp下均使气道进一步狭窄，且滞后现象明显。迷走神经刺激时，较小气道比较大气道狭窄更明显。迷走神经刺激未改变P-V曲线的呼气支，但在所有Ptp下均使吸气容积略有降低（P<0.01）。我们得出结论，体内张力是由迷走神经控制的，它影响气道的物理特性，但不影响肺的物理特性，使气道明显独立于肺实质。
