INTESTINAL TRANSPORT IN CONSTIPATION AND DIARRHEA
INTESTINAL TRANSPORT IN CONSTIPATION AND DIARRHEA
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DOI：
10.1159/000138424
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发表时间：
1988-02-01
期刊：
影响因子：
3.1
通讯作者：
EWE, K
中科院分区：
文献类型：
--
作者：
EWE, K
大约10升的液体与食物和内源性分泌物一起进入胃肠道，只有不到100 ml或1%的液体与粪便一起离开。肠道转运平衡的微小变化可能导致腹泻或便秘。小肠和大肠的功能在电解质和水的运输方面有明显的不同。小肠的相对渗漏的上皮允许在两个方向上快速平衡渗透压，而结肠的紧密上皮一旦被吸收就保存电解质和水。它可以在一定程度上补偿例如由细菌毒素引起的小肠分泌性腹泻，除非它被淹没，导致溢出型腹泻。另一方面，结肠内液体净转运的微小变化也会导致腹泻或便秘，因为其背后没有补偿机制，参与调节跨肠电解质和水运动的机制是提供能量的Na+，K+-ATP酶，膜通透性和活性Cl-分泌的介质如cAMP和Ca 2+，以及影响紧密连接的物质。各种物质可影响这些调节机制中的一种或多种。泻药就是其中之一。
Approximatively 10 liters of fluid enter the gastrointestinal tract with food and endogenous secretions, and only less than 100 ml or 1% leave it with the faeces. Minor changes of this equilibrium in the intestinal transport may cause diarrhoea or constipation. Functions of small and large intestine differ markedly in transport of electrolytes and water. The relatively leaky epithelium of the small intestine allows for rapid equilibrium of osmolality in both directions while the tight epithelium of the colon preserves electrolytes and water once they have been absorbed. It may compensate secretory diarrhoea of the small intestine for instance caused by bacterial toxins to a certain degree unless it is overwhelmed leading to an overflow type of diarrhoea. On the other hand, small changes of net fluid transport in the colon in either direction will lead to diarrhoea or constipation since there is no compensating mechanism behind it. Mechanisms involved in the regulation of transintestinal electrolyte and water movements are the energy providing Na+, K+-ATPase, the mediators of membrane permeability and active Cl–secretion such as cAMP and Ca 2+ and substances affecting the tight junctions. Various substances may affect one or more of these regulatory mechanisms. Laxatives are one of those.