Halm D R, Halm S T, DiBona D R, Frizzell R A, Johnson R D
Department of Physiology, Ohio State University, Columbus 43210, USA.
Am J Physiol. 1995 Oct;269(4 Pt 1):C929-42. doi: 10.1152/ajpcell.1995.269.4.C929.
Stimulation of Cl secretion by prostaglandin E2 (PGE2) was measured as the short-circuit current (Isc) across isolated epithelium of the rabbit distal colon. Cellular morphology of columnar and goblet cells during secretion was monitored using light and electron microscopy. Stimulation by PGE2 altered epithelial cell morphology only by a reduction of vacuolar space in the apical pole of crypt columnar cells, consistent with release of vacuole contents. Imaging of isolated crypts using differential interference microscopy confirmed the release of material from columnar cells during the onset of secretion. Inhibition of Cl secretion with the loop diuretic bumetanide did not block vacuole release. The actin filament-disrupting agent, cytochalasin, reduced the PGE2-stimulated Isc by 40% and blocked emptying of the vacuolar space. These electrical and morphological results indicate that the process of active ion secretion is associated with release of the macromolecular contents from apical vacuoles through a mechanism involving the cytoskeleton. In addition, this relationship supports the concept that vacuolated columnar cells of the crypts of Lieberkühn are the cell type that secretes Cl in response to PGE2.
通过测量跨兔远端结肠分离上皮的短路电流（Isc）来检测前列腺素E2（PGE2）对氯离子分泌的刺激作用。利用光学显微镜和电子显微镜监测分泌过程中柱状细胞和杯状细胞的细胞形态。PGE2刺激仅通过减少隐窝柱状细胞顶端极的液泡空间来改变上皮细胞形态，这与液泡内容物的释放一致。使用微分干涉显微镜对分离的隐窝进行成像，证实了分泌开始时柱状细胞中物质的释放。用髓袢利尿剂布美他尼抑制氯离子分泌并未阻止液泡释放。肌动蛋白丝破坏剂细胞松弛素使PGE2刺激的Isc降低了40%，并阻止了液泡空间的排空。这些电学和形态学结果表明，主动离子分泌过程与顶端液泡中大分子内容物通过涉及细胞骨架的机制释放有关。此外，这种关系支持了这样一种概念，即利伯kühn隐窝的空泡状柱状细胞是响应PGE2分泌氯离子的细胞类型。
