The Effect of Kudingcha (Ilex latifolia Thunb.) on the Contraction of Isolated Guinea-pig Tracheal Smooth Muscle in Vitro

Objective: To study the effects of Kudingcha ( Ilex latifolia Thunb., IL) on the isolated guinea pig tracheal smooth muscle in vitro. Method: By obtaining CaCl 2 and Histamine accumulative dose response curves, to observe the influences of IL on the contraction of tracheal strips induced by calcium and some asthmogenic mediators. Result: CaCl 2 and histamine caused significant contraction of tracheal smooth muscle and pD 2 was 3.55 and 5.34 respectively. After incubated with IL, the dose response curves of CaCl 2 and histamine were significantly shifted to the right, and the maximal contractile force was reduced. IL could also inhibit isolated tracheal strip contraction induced by acetylcholine 3×10 -6 mol·L -1 and histamine 3×10 -6 mol·L -1 , and IC 50 was 0.16mg·ml -1 and 0.21mg·ml -1 . Conclusion: Kudingcha has significant dilated effects on tracheal smooth muscle.