Boskabady M H, Aslani M R, Tabatabaei A
Department of Physiology, Ghaem Medical Centre, Mashhad University of Medical Sciences, Mashhad, Iran.
Pharmacology. 2006;76(1):1-7. doi: 10.1159/000088739. Epub 2005 Oct 4.
There are reports regarding harmful effect of long-term use of beta2-agonist drugs on asthma severity and airway responsiveness. In the present study, the responses of guinea pig trachea with intact and denuded epithelium (groups 1 and 2, n = 10) to methacholine as EC50 were measured in tissues nonincubated or incubated with 10 mumol/l isoprenaline during the resting period. The same protocol was performed in groups 3 and 4 (n = 5 for each group) with an additional 30 min rest time after isoprenaline incubation. The response of trachea with denuded epithelium (groups 2 and 4) to methacholine was significantly higher than that with intact epithelium both in incubated and nonincubated conditions (groups 1 and 3, p < 0.05 to p < 0.001). Incubation with isoprenaline caused a significant reduction in the tracheal response to methacholine in both the denuded groups (p < 0.005 and p < 0.001) and intact epithelium groups (p < 0.005 for both cases). The reduction in tracheal responsiveness to methacholine due to incubation in epithelium denuded trachea (groups 2 and 4) was nonsignificantly greater than that of intact epithelium tissues. There was no difference between groups 3 and 4 with those of groups 1 and 2 in both incubated and non incubated conditions. The maximum contractility response to methacholine was not different between tracheal chains with denuded and intact epithelium and did not change due to incubation with isoprenaline. The results of this study indicate reduction of tracheal response to methacholine due to incubation of tissues with isoprenaline, which was relatively more pronounced in epithelium denuded trachea.
有报告指出长期使用β2-激动剂药物对哮喘严重程度和气道反应性有有害影响。在本研究中，对豚鼠完整上皮和去上皮气管（第1组和第2组，n = 10）在静息期未孵育或用10 μmol/L异丙肾上腺素孵育的组织中，测量对乙酰甲胆碱的反应作为半数有效浓度（EC50）。第3组和第4组（每组n = 5）采用相同方案，在异丙肾上腺素孵育后额外休息30分钟。在孵育和未孵育条件下，去上皮气管（第2组和第4组）对乙酰甲胆碱的反应均显著高于完整上皮气管（第1组和第3组，p < 0.05至p < 0.001）。用异丙肾上腺素孵育导致去上皮组（p < 0.005和p < 0.001）和完整上皮组（两种情况均为p < 0.005）对乙酰甲胆碱的气管反应显著降低。去上皮气管（第2组和第4组）因孵育导致的对乙酰甲胆碱气管反应性降低比完整上皮组织略大，但无显著差异。在孵育和未孵育条件下，第3组和第4组与第1组和第2组之间均无差异。去上皮和完整上皮气管链对乙酰甲胆碱的最大收缩反应无差异，且不因用异丙肾上腺素孵育而改变。本研究结果表明，组织用异丙肾上腺素孵育会导致气管对乙酰甲胆碱的反应降低，这在去上皮气管中相对更明显。
