Mechanism of salivary secretion and activation of paracellular pathway.

为了阐明液体分泌的细胞旁途径的形态学变化，采用深蚀刻冷冻断裂（FF）复制品，用透射电镜（TEM）观察了TJs的细胞骨架。用1 μM浓度的丙二醇（CCh）和异丙肾上腺素（IPR）刺激离体颌下腺（SMGs）。CCh/IPR刺激后，细胞质膜下的细胞骨架细丝呈较厚的排列。CCh/IPR引起胞外分泌过程中膜下肌动蛋白细胞骨架的收缩可能导致TJ链的重排，并调节细胞旁通透性的增加。

To elucidate the morphological change of the paracellular route for fluid secretion, the cytoskeleton of TJs were examined by TEM, using deep etching freeze-fracture (FF) replicas. Isolated submandibular glands (SMGs) were stimulated with 1 μM of carbachol (CCh) and isoproterenol (IPR). After CCh/IPR stimulation, cytoskeletal filaments beneath the plasma membrane were arranged in a thicker layer. Contraction of the submembranous actin cytoskeleton during exocytosis elicited by CCh/IPR may cause rearrangement of TJ strands, and modulate increased paracellular permeability.