中枢外源性P物质对大鼠胃电-机械活动的影响

目的大鼠侧脑室给药观察中枢外源性P物质(SP)对胃电-机械活动和体表胃电活动(EGG)的影响,应用SP受体拮抗剂和阿托品探究SP作用的受体机制;比较冷应激后胃对SP和SP受体拮抗剂的动力学反应性的变化。方法雄性Wistar大鼠44只,随机分为7组:正常对照,SP,SP受体拮抗剂,阿托品,冷应激对照,冷应激+SP,冷应激+SP拮抗剂。冷应激大鼠模型制备后,进行体内慢波、快波及胃窦环行肌运动、体表胃电记录。结果①侧脑室SP给药10μL(1×10-8mol/L),能引起胃窦运动明显增强(P<0.05)。②应激使胃运动幅度极显著升高、频率加快(P<0.01),应激后大鼠对侧脑室注入P物质的胃动力学反应性较前明显增强(P<0.05)。③在本实验中,未发现侧脑室注射SP受体拮抗剂(犤D-Pro2,D-Phe7,D-Trp9犦-SubstanceP)10μL(1×10-8mol/L),有阻断内源性SP引起胃窦收缩的作用。侧脑室注射M受体阻断剂阿托品10μL(1×10-7mol/L),不能阻断脑内P物质对胃的收缩效应。结论中枢注入的P物质可以作为促进胃电-机械活动的调节因子参与中枢增强胃肠的调控。

Effect of intraventricular administration of exogenous substance P on gastric electromechanical activity in rat

AIM:To observed the effect of intracerebral ventricular administration of exogenous substance P (SP) on gastric electromechanical activity and abdominal electrogastrography (EGG), and investigated the receptor mechanisms of SP through application of SP receptor antagonists and atropine.The gastrokinetic responses to SP and SP receptor antagonist after cold stress were also compared. METHODS:44 male Wistar rats were randomly divided into 7 groups: normal control; SP; SP antagonist; Atropine; cold stress control; cold stress+ SP and cold stress+ SP antagonist groups.RESULTS:① Intracerebral ventricular administration of SP 10 μ L(1× 10－ 8 mol/L) significantly improved the movement of gastric sinus(P< 0.05);② Cold stress elevated the amplitude and frequency of gastric movement. The gastrokinetic response to intracerebral ventricular injection of SP in rats significantly enhanced (P< 0.05) after stress compared with the baseline;③ In the experiment, there was no significant effect of SP receptor antagonist (D-Pro2,D-Phe7,D-Trp9] Substance P) 10 μ L (1× 10－ 8mol/L), in blocking intrinsic SP up Atrium contraction. Intracerebral ventricular injection of M receptor blocker,Atropine(10 μ L 1× 10－ 7 mol/L), failed to block the gastric contraction effect of cerebral SP. CONCLUSION:SP administered into the cerebral ventricle plays a role in the regulation of gastrointestinal movement through the improvement of gastric electromechanical activity.