Mitchell R W, Ndukwu I M, Arbetter K, Solway J, Leff A R
Section of Pulmonary and Critical Care Medicine, University of Chicago, Illinois 60637.
Am J Physiol. 1993 Dec;265(6 Pt 1):L549-54. doi: 10.1152/ajplung.1993.265.6.L549.
We studied the effect of either 1) immunogenic inflammation caused by aerosolized ovalbumin or 2) neurogenic inflammation caused by aerosolized capsaicin in vivo on guinea pig tracheal smooth muscle (TSM) contractility in vitro. Force-velocity relationships were determined for nine epithelium-intact TSM strips from ovalbumin-sensitized (OAS) vs. seven sham-sensitized controls and TSM strips for seven animals treated with capsaicin aerosol (Cap-Aer) vs. eight sham controls. Muscle strips were tethered to an electromagnetic lever system, which allowed isotonic shortening when load clamps [from 0 to maximal isometric force (Po)] were applied at specific times after onset of contraction. Contractions were elicited by supramaximal electrical field stimulation (60 Hz, 10-s duration, 18 V). Optimal length for each muscle was determined during equilibration. Maximal shortening velocity (Vmax) was increased in TSM from OAS (1.72 +/- 0.46 mm/s) compared with sham-sensitized animals (0.90 +/- 0.15 mm/s, P < 0.05); Vmax for TSM from Cap-Aer (0.88 +/- 0.11 mm/s) was not different from control TSM (1.13 +/- 0.08 mm/s, P = NS). Similarly, maximal shortening (delta max) was augmented in TSM from OAS (1.01 +/- 0.15 mm) compared with sham-sensitized animals (0.72 +/- 0.14 mm, P < 0.05); delta max for TSM from Cap-Aer animals (0.65 +/- 0.11 mm) was not different from saline aerosol controls (0.71 +/- 0.15 mm, P = NS). We demonstrate Vmax and delta max are augmented in TSM after ovalbumin sensitization; in contrast, neurogenic inflammation caused by capsaicin has no effect on isolated TSM contractility in vitro. These data suggest that airway hyperresponsiveness in vivo that occurs in association with immunogenic or neurogenic inflammation may result from different effects of these types of inflammation on airway smooth muscle.
我们研究了以下两种情况对豚鼠气管平滑肌（TSM）体外收缩性的影响：1）雾化卵清蛋白引起的免疫原性炎症，或2）雾化辣椒素引起的神经源性炎症。测定了来自卵清蛋白致敏（OAS）的9条上皮完整的TSM条带与7条假致敏对照的力-速度关系，以及7只接受辣椒素气雾剂（Cap-Aer）处理的动物的TSM条带与8只假对照的力-速度关系。肌肉条带连接到电磁杠杆系统，在收缩开始后的特定时间施加负载钳制[从0到最大等长力（Po）]时，该系统允许等张缩短。通过超强电场刺激（60Hz，持续10秒，18V）引发收缩。在平衡过程中确定每条肌肉的最佳长度。与假致敏动物（0.90±0.15mm/s，P<0.05）相比，OAS的TSM中最大缩短速度（Vmax）增加（1.72±0.46mm/s）；Cap-Aer的TSM的Vmax（0.88±0.11mm/s）与对照TSM（1.13±0.08mm/s，P=无显著性差异）无差异。同样，与假致敏动物（0.72±0.14mm，P<0.05）相比，OAS的TSM中最大缩短量（δmax）增加（1.01±0.15mm）；Cap-Aer动物的TSM的δmax（0.65±0.11mm）与盐水气雾剂对照（0.71±0.15mm，P=无显著性差异）无差异。我们证明卵清蛋白致敏后TSM中的Vmax和δmax增加；相比之下，辣椒素引起的神经源性炎症对体外分离的TSM收缩性没有影响。这些数据表明，与免疫原性或神经源性炎症相关的体内气道高反应性可能是由这些类型的炎症对气道平滑肌的不同作用导致的。
