Permeability of the rat small intestinal epithelium along the villus-crypt axis:: Effects of glucose transport
Permeability of the rat small intestinal epithelium along the villus-crypt axis:: Effects of glucose transport
复制标题
DOI：
10.1053/gast.2000.18148
复制
发表时间：
2000-10-01
期刊：
影响因子：
29.4
通讯作者：
Jodal, M
中科院分区：
文献类型：
--
作者：
Fihn, BM;Sjöqvist, A;Jodal, M
背景和目标：本研究的目的是阐明上皮细胞沿着绒毛-隐窝轴的通透性特征，并探讨葡萄糖转运对这些特征的影响沿着这一轴。研究方法：C-14-甘露醇和Cr-51 w-EDTA或H-3-菊粉的消失率被确定为从麻醉大鼠空肠腔的再循环灌注系统的清除率（Cix）。净液体运输在很大的范围内变化，通过交换甘露醇与葡萄糖的灌注液中，并通过抑制神经介导的分泌过程与六甲双铵。结果：随着净液体转运（分泌8.50 +/- 1.88，吸收16.72 +/- 1.75 μ L.min（-1）.g（-1））和葡萄糖灌注液的增加，CIMan显著增强。CICr-EDTA是恒定的，无论净液体运输，并减少到微不足道的值在0.2 mL/min的灌注速率。CIIn是没有什么不同的零。结论：绒毛的吸收顶端部分含有小孔（半径< 6埃），允许通过溶剂拖曳进行被动转运，例如，在一些实施方案中，囊腔中的孔是大的（50-60埃），并且管腔内容物无法进入。绒毛的基部含有中等大小的孔（10-15埃），通过这些孔不会发生溶剂拖曳。大鼠中的主动葡萄糖转运主要增加了可用于被动转运的小孔的数量，而这些小孔的大小似乎保持恒定。
Background & Aims: The aim of this study was to elucidate the permeability characteristics of the epithelium along the villus-crypt axis and investigate the effect of glucose transport on these characteristics along this axis. Methods: The disappearance rates of C-14-mannitol and Cr-51w-EDTA or H-3-inulin were determined as clearance (CIx) from a recirculating perfusion system of the jejunal lumen in anesthetized rats. Net fluid transport was varied over a large range by exchanging mannitol with glucose in the perfusate solution and by inhibition of nervously mediated secretory processes with hexamethonium. The perfusion rate was 0.5 or 0.2 mL/min. Results: CIMan enhanced significantly with increasing net fluid transport (secretion 8.50 +/- 1.88, to absorption 16.72 +/- 1.75 mu L.min(-1).g(-1)) and with glucose perfusates. CICr-EDTA was constant irrespective of net fluid transport and was reduced to insignificant values at a perfusion rate of 0.2 mL/min. CIIn was not different from zero. Conclusions: The absorbing apical part of the villus contains small pores (radius, < 6 Angstrom) allowing passive transport via solvent drag of, e.g., monosaccharides, whereas the pores in the crypts are large (50-60 Angstrom) and inaccessible to the luminal content. The basal part of the villus contains medium-sized pores (10-15 Angstrom) through which no solvent drag occurs. Active glucose transport in the rat mainly increases the number of small pores accessible for passive transport, whereas the size of these pores seems to stay constant.