Morphological evidence of paracellular transport in perfused rat submandibular glands.
Morphological evidence of paracellular transport in perfused rat submandibular glands.
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DOI：
10.2152/jmi.56.395
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
S. Hashimoto;M. Murakami
中科院分区：
文献类型：
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作者：
S. Hashimoto;M. Murakami
液体分泌的细胞旁途径的形态学改变仍然是一个长期存在的问题。本研究的目的是可视化的卡巴胆碱（CCh）和异丙肾上腺素（IPR）治疗灌注大鼠下颌下腺（SMG），使用冷冻断裂（FF）复制品的快速冷冻组织引起的紧密连接的细胞骨架结构的变化。用1 μ M CCh和IPR灌注和刺激来自雄性Wistar大鼠的分离SMG。标本立即通过金属接触用液氦快速冷冻。在切割和深蚀刻后，通过旋转阴影获得FF复制品，并通过透射电子显微镜进行检查。在CCh/IPR刺激后，TJ的链颗粒重排为自由端和末端环。在垂直断面，质膜下的细胞骨架丝排列在一个较厚的层比那些没有刺激的腺体。CCh/IPR引起的胞吐过程中膜下肌动蛋白细胞骨架的收缩可能会导致TJ链的重排，这是由于TJ膜颗粒和肌动蛋白丝之间通过微小的桥接结构的直接相互作用。TJ膜颗粒的重排和运动涉及通过间质分子的中介重建腔下膜肌动蛋白丝网络，并可调节CCh/IPR刺激后增加的细胞旁通透性。
The morphological change of the paracellular route for fluid secretion is still a long-standing question. The purpose of this study was to visualize alterations in the cytoskeleton structure of tight junctions caused by carbachol (CCh) and isoproterenol (IPR) treatment of perfused rat submandibular glands (SMGs), using freeze-fracture (FF) replicas of rapidly frozen tissues. Isolated SMGs from male Wistar rats were perfused and stimulated with 1 microM CCh and IPR. Specimens were immediately rapidly frozen with liquid helium by metal contact. After cutting and deep etching, FF replicas were obtained by rotary shadowing and were examined by transmission electron microscopy. After CCh/IPR stimulation, the strand particles of TJs rearranged with free ends and terminal loops. In the vertical fracture surface, cytoskeletal filaments beneath the plasma membrane were arranged in a thicker layer than those of the gland without stimulation. Contraction of the submembranous actin cytoskeleton during exocytosis elicited by CCh/IPR may cause rearrangement of TJ strands due to direct interactions between the TJ membrane particles and actin filaments via the tiny bridging structures. The rearrangement and movement of TJ membrane particles involves reconstruction of the subluminal membranous actin filament network through the intermediary of interstitial molecules and may modulate increased paracellular permeability after CCh/IPR stimulation.