麻仁软胶囊在诱导大鼠结肠上皮细胞阴离子分泌中的作用  

Cellular mechanism underlying Maren soft capsule (麻仁软胶囊) induced anion secretion in rat colon

作　　者：杨孜欢[1] 潘奥[1] 陈思亮[1] 周文良[1] 

机构地区：[1]中山大学生命科学学院,广州510275

出　　处：《中药药理与临床》2008年第4期1-5,共5页Pharmacology and Clinics of Chinese Materia Medica

摘　　要：目的：探讨麻仁胶囊对大鼠结肠上皮电解质转运的影响和机制。方法：在药物和特异性通道阻断剂的作用下，用短路电流（ISC）技术，体外测量跨结肠上皮电解质转运的变化；并且用ELISA方法测定火麻仁对结肠上皮细胞内cAMP浓度的影响。结果：在结肠上皮的浆膜面加入麻仁胶囊（0．1～25mg／ml），能产生一个剂量依赖性的短路电流，EC50为2．88±0．39mg／ml；将Cl^-或HCO3^-从浴液中替换掉以后，分别将火麻仁诱导的短路电流抑制了78．3％（n=4，P〈0．05）和28．3％（11=4，P〈0．05），当两种阴离子同时被替换后，该电流减少了97．8％（n=4，P〈0．01）；在结肠上皮的黏膜面用Na^＋通道阻断剂amiloride（100μM）预处理后，不影响随后由该药产生的短路电流；而该短路电流能被黏膜面Cl^-通道非选择性阻断剂DPC（1mM）完全阻断，但对DIDS（100M）（Ca^2＋激活的Cl^-通道阻断剂）不敏感；在结肠上皮的浆膜面加入Na^＋-K^＋-2Cl^-共转运体（NKCC）阻断剂bumetanide（100M）能完全抑制该药产生的短路电流；浆膜面K^＋通道阻断刑quindine（100M）能部分抑制该药在结肠上皮产生的短路电流（n=4，P〈0．01）。胞内腺苷酸环化酶（AC）的抑制剂MDL-12330A（20M）预处理结肠上皮30分钟后，显著抑制了该药诱导的短路电流增加；在ELISA测定结肠上皮胞内[cAMP]i的实验中，该药被证实能升高胞内[cAMP]i。结论：麻仁胶囊能呈剂量依赖性地刺激大鼠远端结肠上皮的阴离子分泌；通过升高胞内[cAMP]i激活黏膜面上的CFTR通道，并且共同作用位于基底膜面的NKCC和K通道，从而促进结肠上皮的水和电解质转运。Objective：Maren Soft Capsule （MRSC） is a Chinese medicine-based formula for anti-constipation. The aim of this study was to investigate the possible effect of MRSC on the rat colonic mucosa. Administration of MRSC induces anion secretion across rat colonic mucosa. Methods ： 1 ） MRSC was applied to colonic epithelial cells bathed in normal or ingredient-free solutions to induce a short circuit current; 2） Addition of different inhibitors and ELISA cAMP measurement uncovered the intracellular pathway involved in ISC induced by MRSC. Results： Mucosal addition of MRSC （0. 1 -25mg/ml） elicited a concentration dependent, and sustained increase in short-circuit current （Isc）. In intact isolated colonic strips, MRSC induced a long lasting lsc which was inhibited in CI or HCO3^- free Kreb＇s solution or by inhibiting basolateral chloride uptake with bumetanide and DPC, but this current was not inhibited by 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid （DIDS）. In chloride free Kreb＇s solution, MRSC induced lsc increase was significantly inhibited by Acetazolamide which was the inhibitor of carbonic anhydrase. Pretreated the isolated colonic strips with MDL-12330A for 30 minutes can result significandy reduction of MRSC-induced Isc, it suggest that the MRSC evoked the Ise increase, possibly via a cAMP-dependent pathway. Using ELISA cAMP mesurement methods, we found MRSC treatment also resulted in increased cAMP content in rat colon. The anion secretion was significantly inhibited by the qunindine （100μM） , a specific inhibitor of K^＋ channels, suggesting that some kinds of K^＋ channels are important in maintaining the cAMP-dependent anion secretion induced by MRSC in rat colons. Conclusion： MRSC stimulated anion secretion in rat distal colon via increase in cellular cAMP resulting in the activation of apical CFTR Cl^- channels.

关 键 词：麻仁软胶囊 结肠上皮 短路电流 阴离子分泌 

分 类 号：R285[医药卫生—中药学]