侧柏叶乙酸乙酯提取物对豚鼠离体气管平滑肌的作用

用离体豚鼠气管条，探讨侧柏叶乙酸乙酯提取物对气管平滑肌作用。结果表明，侧柏叶乙酸乙酯提取物能抑制乙酰胆碱，氯化钾所致气管平滑肌收缩，而且能使乙酰胆碱收缩气管平没肌的量效曲线右移，并抑制最大效应，其作用为剂量依赖性心肌肥厚提示侧柏叶乙酸乙酯提取物松驰气管平滑肌作用机制可能与影响Ｃａ＾２＋的跨膜转运有关。

Action of Chinese Arborvitae Top Tender Leaves (Platycladus orientalis) on Smooth Muscle of Guinea Pig Trachea

The mechanism of antiasthmatic action of the ethyl acetate soluble fraction of extract of Platycladus orientalis (L. ) Franco was studied with smooth muscle of isolated guinea pig trachea. The results indicated that P. orientalis could significantly Inhibit the contraction of isolated guinea pig trachea preparations induced by acetylcholine (ACh) and KCI. P. orientalis shifted the dose response curves for ACh nonparallelly to right and depress their maximal response, in a dose dependent manner. These results suggested that the antagonistic effects of P. orientalis on smooth muscle contraction induced by the two agonists may be mainly related to action of P. orientalis in blocking calcium channel of tracheal smooth muscle.