Ishida K, Paré P D, Thomson R J, Schellenberg R R
University of British Columbia Pulmonary Research Laboratory, St. Paul's Hospital, Vancouver, Canada.
J Appl Physiol (1985). 1990 Apr;68(4):1316-20. doi: 10.1152/jappl.1990.68.4.1316.
Repeated aerosol antigen challenge of previously sensitized guinea pigs induces airway hyperresponsiveness to inhaled acetylcholine. To determine the mechanism producing these airway changes and assuming that changes in the trachealis muscle reflect changes in muscle of the entire tracheobronchial tree, we examined the in vitro smooth muscle mechanics and morphometric parameters of tracheae from guinea pigs demonstrating hyperresponsiveness in vivo vs. tracheae from control guinea pigs. No differences between these groups were found in luminal volume at zero transmural pressure, passive pressure-volume characteristics, or area of airway wall. Smooth muscle areas were slightly less in tracheae from hyperresponsive guinea pigs. Tracheae from hyperresponsive guinea pigs had both significantly increased isovolumetric force generation and isobaric shortening compared with tracheae from controls when evaluated over the range of transmural pressures from -40 to 40 cmH2O. We conclude that the in vivo airway hyperresponsiveness induced with repeated antigen challenge is associated with both increased force generation and shortening of tracheal smooth muscle without increased muscle mass, suggesting enhanced contractile activity.
对先前致敏的豚鼠反复进行气溶胶抗原激发可诱导气道对吸入乙酰胆碱的高反应性。为了确定产生这些气道变化的机制，并假设气管肌的变化反映了整个气管支气管树肌肉的变化，我们检测了在体内表现出高反应性的豚鼠气管与对照豚鼠气管的体外平滑肌力学和形态学参数。在零跨壁压下的管腔容积、被动压力-容积特性或气道壁面积方面，这些组之间未发现差异。高反应性豚鼠的气管平滑肌面积略小。当在-40至40 cmH₂O的跨壁压范围内进行评估时，与对照组的气管相比，高反应性豚鼠的气管等容力产生和等压缩短均显著增加。我们得出结论，反复抗原激发诱导的体内气道高反应性与气管平滑肌力产生增加和缩短有关，而肌肉质量并未增加，提示收缩活性增强。
