Regulation of epithelial tight junction permeability by cyclic AMP.

摘要: In ‘leaky‘ epithelia, ions move through both a transcellular and paracellular (serial alignment of tight junction intercellular space) path. The efficiency transepithelial transport could therefore be regulated if the cell was able to alter reversibly permeability junctions. (These are specialized regions apical membranes common all epithelia.) We now report that such mechanism indeed exists in Necturus gallbladder. It is effected by cyclic AMP, which already known mediate surface membrane phenomena variety systems its interaction with cytoskeletal system1,2. gallbladders mounted perfused electrolyte solutions an Ussing-type chamber, exposure mucosal AMP analogues increased electrical resistance, potential difference short-circuit current decreased NaCl dilution potentials rapid reversible manner. also observed depolarization slow decline intracellular K+ activity. Freeze-fracture electron microscopy tissues fixed glutaraldehyde during peak response showed reorientation intramembranous junctional fibrils, suggesting reduces ionic pathway this epithelium altering structure