Diquat (1,1'-ethylene-2,2'-bipyridilium) is a non-selective desiccant herbicide which, when administered orally to mammalian species, causes significant secretion of fluid into the lumen of the gastrointestinal tract. In order to characterize this secretory response in more detail the effect of sublethal doses of diquat dibromide (DQBr2) on intestinal secretion was investigated in vivo in the jejunum of anaesthetized rats. 2. Ligated segments of jejunum (10 cm) which were prepared in groups of up to five animals were filled with 500 microliters of isosmotic DQBr2 solutions with concentrations ranging from 1-100 mM and maintained in the anaesthetized rat for 1, 2 or 3 h; in control experiments a solution of 100 mM NaBr was used. 3. It was found that while all of the fluid instilled into the segments was absorbed in the control experiments, there was both a dose- and time-dependent secretory response to DQBr2. Maximal fluid secretion occurred after treatment with 50 mM DQBr2 for 3 h. 4. Histological assessment of the jejunum revealed an increase in cell exfoliation and evidence of luminal distension after incubation with DQBr2. However, no structural damage to the mucosa could be seen to account for the fluid secretion. 5. The model described provides a quantitative means of evaluating intestinal secretion and may be used for elucidating the mechanism by which diquat alters fluid transport processes.
摘要
敌草快（1,1'-亚乙基-2,2'-联吡啶鎓）是一种非选择性的干燥剂除草剂，当给哺乳动物口服时，会导致大量液体分泌到胃肠道腔内。为了更详细地描述这种分泌反应，研究了在麻醉大鼠空肠中，亚致死剂量的二溴化敌草快（DQBr2）对肠道分泌的影响。2. 将空肠结扎段（10厘米）以每组最多五只动物的方式制备，用浓度范围为1-100 mM的500微升等渗DQBr2溶液填充，并在麻醉大鼠中维持1、2或3小时；在对照实验中，使用100 mM NaBr溶液。3. 结果发现，在对照实验中注入段内的所有液体都被吸收，而对DQBr2存在剂量和时间依赖性的分泌反应。用50 mM DQBr2处理3小时后出现最大液体分泌。4. 空肠的组织学评估显示，与DQBr2孵育后，细胞脱落增加且有管腔扩张的迹象。然而，未见黏膜有结构损伤可解释液体分泌。5. 所描述的模型提供了一种评估肠道分泌的定量方法，可用于阐明敌草快改变液体转运过程的机制。
