【作者】 任银祥；

【导师】 宋焱峰；

【作者基本信息】 兰州大学 ， 人体解剖学与组织胚胎学， 2008， 硕士

【摘要】 目的:观察A型肉毒毒素（botulinum toxin type A,BTX-A）对内源性和外源性P物质（substance P,SP）引发的大鼠离体幽门平滑肌收缩的作用,并探索其作用机理。方法:①应用电场刺激（electrical ficld stimulation,EFS）诱导幽门平滑肌内源性神经递质释放,引发平滑肌收缩,用阿托品（Atropine,Atr）阻断胆碱能神经后分别观察NK₁受体拮抗剂[D-Arg¹,D-Phe⁵,D-Trp^7,9,Leu¹¹]-substance P(DDDL-SP,1μmol·L^-1,n=10)和BTX-A(10U·mL^-1,n=10)对肌条收缩的影响;②每隔30min加入SP(1μmol·L^-1)诱发孵育在不同剂量的BTX-A(4U·mL^-1,n=8;10U·mL^-1,n=8)中的肌条收缩,持续记录4h,分析BTX-A抑制SP引起平滑肌收缩的量效和时效作用。结果:①EFS增加平滑肌收缩振幅（P＜0.05）、频率和张力（P＜0.01）;该作用可被阿托品(1μmol·L^-1)不完全抑制,尚存的余波可分别被DDDL-SP(1μmol·L^-1)抑制（振幅P＜0.05,张力和频率P＜0.01）,或被BTX-A(10U·mL^-1)抑制（振幅P＜0.05,张力、频率P＜0.01）,BTX-A抑制后的余波不再被DDDL-SP进一步抑制。②分别用低剂量(4U·mL^-1)和高剂量(10U·mL^-1)的BTX-A孵育幽门平滑肌条,并每隔30 min加入SP(1μmol·L^-1)连续观察4h,两组SP诱导的收缩张力均随时间逐渐降低,第4h时,BTX-A低剂量组收缩张力为SP诱导的原发张力的73.36±11.46%（P=0.011＜0.05）,而高剂量组为25.09±8.08%（P=0.000＜0.01）。结论:EFS可诱导离体胃幽门平滑肌释放内源性ACh和SP;BTX-A对EFS诱发的内源性SP引起的幽门平滑肌收缩有抑制作用;BTX-A对外源性SP引起的幽门平滑肌收缩亦有抑制作用,且该作用呈时间、剂量依赖性。更多还原

【Abstract】 Objective:To investigate the effect and mechanism of botulinum toxin type A （BTX-A）on endo- and exo-genous substance P（SP）-induced contractility in the pyloric muscle strips in rats.Methods:（1）Electrical field stimulation（EFS）was used to induce contraction of pyloric circular muscle strips incubated in Krebs bicarbonate buffer via enhancing neurotransmitter release.An antagonist of NK1-receptor([D-Arg¹,D-Phe⁵,O-Trp^7,9, Leu¹¹]-substance P,1μmol.L^-1,DDDL-SP,n=10)or BTX-A(10 U·mL^-1,n=10)was respectively administrated following atropine(1μmol·L^-1)treatment for observing these inhibitory effect on endogenous SP-induced contractibility.（2）SP(1μmol·L^-1) was added once every 30 min into organ bath in which pyloric circular muscle strips were suspended and contained the different concentration of BTX-A(4 U·mL^-1,n=8 and 10 U·mL^-1,n=8)in Krebs bicarbonate buffer for 4 hours in order to estimate the inhibitory effects of BTX-A on exogenous SP-induced contractile response.Results:（1）Pyloric strips contractility was enhanced including the amplitude（P＜0.05）,frequency and tension（P＜0.01）by EFS.The EFS-induced pyloric contractile response was inhibited partly by atropine,an antagonist of cholinergic muscarinic receptor.The residual contractility in pyloric muscle strips was further decreased by subsequent administration of DDDL-SP(1μmol·L^-1),an antagonist of NK₁-receptor, or BTX-A(10 U·mL^-1).（2）The pyloric muscle strips were incubated in BTX-A with low concentration(4 U·mL^-1)or higher concentration(10 U·mL^-1),and SP(1μmol·L^-1)was added once every 30 min during 4 hours.SP-induced contractile response was gradually decreased along with time in two groups.In addition,the decrease volumes of SP-induced contractile tension between two groups of BTX-A were significantly different at the 4^thhour,the inhibitory ratios were 73.36±11.46%in low dose group（P=0.011＜0.05）and 25.09±8.08%in high dose group（P=0.000＜0.01）respectively compared to SP-induced contractile tension without BTX-A.Conclusion:EFS-induced contraction in pyloric muscle strips is partly suppressed by atropine,residual contractile waves are similarly inhibited by DDDL-SP or BTX-A.These results suggest that EFS induces ACh and endo-genous SP release and pyloric contraction is the endo-genous SP-induced contractily is inhibited by BTX-A. Exo-genous SP-induced contractility of the pyloric smooth muscle strips is inhibited by BTX-A with a time- and dose-dependent.更多还原