Yau K I, Ko F N, Chien C H
Department of Pediatrics, College of Medicine, National Taiwan University, Taipei, Taiwan.
J Formos Med Assoc. 1999 Aug;98(8):567-72.
We investigated the effects of two prokinetic agents, metoclopramide and cisapride, on the contractile response of isolated guinea pig tracheal segments exposed to electrical field stimulation (EFS). Tracheal segments were suspended between two platinum electrodes in organ baths. Frequency-response curves were obtained by increasing the frequency of the stimuli on equilibrated tracheal segments, in a stepwise manner. Metoclopramide potentialed the EFS-induced contraction of the tracheal; the potentiation was more prominent at lower stimulation frequencies (< or = 10 Hz). Cisapride significantly inhibited the electrically stimulated contraction in trachea strips when the frequency of the stimulus was higher than 10 Hz. In the presence of both metoclopramide and cisapride, there was a potentiation of the contractile response at lower frequencies, and this potentiation was reduced when the frequency was higher than 10 Hz. These results demonstrate that metoclopramide enhances and cisapride reduces the airway tonicity elicited by EFS in isolated guinea pig trachea segments. Further studies are needed to verify the effects of these prokinetic agents on EFS-induced contraction of isolated guinea pig trachea and to determine the mechanisms involved.
我们研究了两种促动力药物甲氧氯普胺和西沙必利对暴露于电场刺激（EFS）的离体豚鼠气管段收缩反应的影响。气管段悬挂于器官浴槽中的两个铂电极之间。通过逐步增加平衡状态下气管段刺激频率来获得频率-反应曲线。甲氧氯普胺增强了EFS诱导的气管收缩；在较低刺激频率（≤10Hz）时这种增强更为显著。当刺激频率高于10Hz时，西沙必利显著抑制气管条的电刺激收缩。在同时存在甲氧氯普胺和西沙必利的情况下，低频时收缩反应增强，而当频率高于10Hz时这种增强作用减弱。这些结果表明，甲氧氯普胺增强而西沙必利降低了EFS在离体豚鼠气管段中引起的气道张力。需要进一步研究来验证这些促动力药物对离体豚鼠气管EFS诱导收缩的作用，并确定其中涉及的机制。
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