目的 考察羚贝止咳糖浆对豚鼠离体气管螺旋条平滑肌收缩的抑制作用，并探讨其作用机制。方法 制备豚鼠离体气管平滑肌螺旋条，随机分为羚贝止咳糖浆组、川贝雪梨糖浆组和异丙肾上腺素组，每组各3例。加入0.167 μg/mL氯化乙酰胆碱制备豚鼠离体气管螺旋条平滑肌收缩模型。当气管平滑肌张力达到最高点时，观察羚贝止咳糖浆最大有效浓度对豚鼠离体气管螺旋条收缩作用的影响，计算抑制率。采用RT-PCR法检测豚鼠离体气管条肌球蛋白轻链激酶（MLCK）mRNA表达，采用疫蛋白印迹法（Western blotting）法检测豚鼠离体气管条MLCK蛋白表达情况。结果 羚贝止咳糖浆能够显著抑制氯化乙酰胆碱引起的豚鼠气道平滑肌过度收缩，松弛气道平滑肌，作用强度强于川贝雪梨糖浆（P<0.05），但弱于异丙肾上腺素（P<0.01）。羚贝止咳糖浆能够显著降低由氯化乙酰胆碱引起的过度收缩的豚鼠气道平滑肌中MLCK mRNA表达、MLCK的蛋白表达量（P<0.01）。结论 羚贝止咳糖浆可能通过减少处于过度收缩状态的平滑肌MLCK mRNA、MLCK蛋白的表达量，起到松弛气道平滑肌、解除气道痉挛的作用，从而发挥其止咳平喘的作用。

Objective To study inhibition of Lingbei Zhike Syrup on contraction of smooth muscle of tracheal spiral strips in guinea pig, and explore its mechanism. Methods Tracheal spiral lines in guinea pig were isolated and prepared, and were randomly divided into Lingbei Zhike Syrup group, Chuanbei Xueli Syrup group, and isoproterenol group, and each group had three tracheal spiral strips. Acetylcholine chloride (0.167 μg/mL) was used to prepare contraction models of smooth muscle of tracheal spiral strips in guinea pig. When tension was the maximum, effects of Lingbei Zhike Syrup with maximum concentration on contraction of smooth muscle of tracheal spiral strips in guinea pig were observed, and inhibition rates were calculated. RT-PCR method was used to detect the expressions of myosin light chain kinase (MLCK) mRNA. Western blotting method method was used to detect expressions of MLCK protein in guinea pig. Results Lingbei Zhike Syrup could inhibit excessive contraction of airway smooth muscle induced by acetylcholine chloride, and relax airway smooth muscle. The effect of Lingbei Zhike Syrup was stronger than that of Chuanbei Xueli Syrup (P < 0.05), but weaker than that of isoproterenol (P < 0.01). Lingbei Zhike Syrup could significantly decrease the expression of MLCK mRNA expression and MLCK protein in airway smooth muscle with excessive contraction in guinea pigs induced by acetylcholine chloride. Conclusion Lingbei Zhike Syrup can reduce expression of MLCK mRNA and MLCK protein in excessive contraction of smooth muscle, relax airway smooth muscle, and relieve airway spasm, and has antitussive and antiasthmatic effect.

吉林省科技发展计划项目（20150311113YY）