离体大鼠胃扩张时胃泌素生长抑素分泌的变化及机制探讨

Role of somatostatin and cholinergic mechanisms of gastrin release regulation in isolated rat stomach during gastric distention

目的：探讨胃扩张时胃泌素、生长抑素分泌的变化以及胃内神经、体液调节机制在其中的可能作用。方法：用带血管灌流的离体大鼠胃，从胃腔灌注生理盐水造成胃扩张模型，经血管注入神经递质或相应拮抗剂等，观察上述指标变化。结果：胃扩张引起容量依赖性的胃泌素分泌减少及生长抑素分泌增加（ Ｐ＜ ０－０５ ，Ｐ＜ ０－０１） ；从胃动脉注入河豚毒（１０６ ｍｏｌＬ） 或阿托品（１０７ ｍｏｌＬ） ，上述效应分别被阻断５０ ％ 和４０ ％ 左右；注入生长抑素拮抗剂ｃｙｃｏｌ［７ － ａｍｉｎｏｈｅｐｔａｎｏｙｌ－ Ｐｈｅ － Ｄ－ Ｔｒｐ － Ｌｙｓ － Ｔｈｒ（Ｂｚｌ）］（１０６ ｍｏｌＬ） ，胃泌素分泌受抑制现象被阻断６０ ％ ，同时注入阿托品，抑制现象几乎完全被消除。结论：离体大鼠胃扩张抑制胃泌素分泌主要通过胃内胆碱能神经及生长抑素的作用；

AIM:To examine the effect of graded distention of isolated rat stomach on the release of gastrin and somatostatin(SS), and the possible intragastric mechanisms.METHODS and RESULTS:Graded gastric distention by 5, 10, 15 mL saline for 20 minutes caused a significant volume-dependent decrease of gastrin release and increase of SS release. In response to 10 mL distention, infusion of axonalblocker TTX(10 6 mol/L) and cholinergic blocker atropine (10 7 mol/L) attenuated a decrement of gastrin release by 50% and an increment of SS by 40%, respectively. The SS antagonist (SS-A) cyclo [7-aminohepanoyl-Phe-D-Trp-Lys-Thr(Bzl)](10 6 mol/L) attenuated the inhibition of gastrin release by 60%. Furthermore, combined infusion of SS-A and atropine completely abolished distention induced inhibition of gastrin release.CONCLUSIONS:Distention of isolated rat stomach stimulates SS release via cholinergic and non-cholinergic TTX-insensitive pathways. But SS also intragastric cholinergic pathways are responsible for the distention-induced inhibition of gastrin release.