胃动素对Cajal间质细胞引起的大鼠胃平滑肌收缩的作用

目的 观察Cajal间质细胞（ICC）在胃平滑肌收缩的关键作用,以及胃动素及ICC引起胃平滑肌细胞收缩的影响。方法：（1）采用大鼠胃体上1/3起博区及胃窦环行肌条在恒温灌流Kreb液中,通过张力换能器输入生理记录仪记录胃肌条的机械运动。（2）用美蓝 光照选择性损伤ICC对胃平滑肌收缩的影响 。（3）损伤ICC后胃动素对胃肌收缩的影响。结果：（1）带有ICC的胃体起搏区和胃窦肌条记录到稳定的收缩活动,胃窦收缩频率和振幅较胃体起搏区高。（2）损伤胃环肌层ICC后,导致胃体起搏区和胃窦平滑肌收缩频率与振幅下降80%-90%,运动几乎消失。（3）胃动素0.03-0.25μg/ml明显增加胃体起搏区和胃窦的收缩频率和振幅,呈剂量依赖性增加。损伤ICC后几乎完全取消胃动素对胃肌的收缩作用。抗胃动素血清和阿托品可阻断胃动素的作用。结论 ICC是胃平滑肌运动的起搏细胞。胃动素通过ICC对胃肌收缩进行调节。

Effect of motilin on gastric smooth contraction induced by interstitial cells of Cajal

OBJECTIVE: To investigate the role of interstitial cells of Cajal (ICC) in contraction of gastric smooth muscle and the effect of motilin on this role. METHODS: Two kinds of smooth muscle segments with ICC were isolated from the pacemaker area at the upper 1/3 of stomach body and from the gastric antrum of 90 rats and immersed into Krebs solution and linked with tonotransducer to record their contraction. Both kinds of smooth muscle segments were divided into 5 groups equally: group A (control group), group B (methylene blue and intense illumination were used to destroy the ICC therein), group C (motilin was added into the Krebs solution), group D (both motilin and anti-motilin serum were added), and group E (motilin and atropin or hexahydroxy-quaternary ammonium were added). RESULTS: stable contractile activity was recorded in these 2 kinds of smooth muscle segments with higher frequency and amplitude of contraction in those from the gastric antrum than those from the stomach body. The frequency and amplitude of contraction in the smooth muscle segments with the ICC destroyed by methylene blue and intense illumination were decreased by 80% approximately 90%. Motilin increased the frequency and amplitude of contraction in the smooth muscle segments from the gastric antrum and stomach body dose-dependently. Anti-motilin serum and atropin, but not hexahydroxy-quaternary ammonium blocked the effect of motilin. The smooth muscle segments with destroyed ICC showed no significant differences in the frequency and amplitude of contraction in comparison with the smooth muscle segments with destroyed ICC plus motilin. CONCLUSION: The pacemaker cells of the contractile activity of gastric smooth muscle cells are ICC, Motilin regulates the gastric smooth muscle contraction initiated by ICC.