A time course study of water permeability and morphological alterations induced by mucosal hyperosmolarity in frog urinary bladder.

Abstract

The role of the tight junction in the hydrosmotic response of the frog urinary bladder has been analysed by comparative kinetic studies and freeze etching examination. The comparison of the time course of the variations in transepithelial water net flux and of the alterations of tight junction ultrastructure in bladders exposed to mucosal hyperosmolar solutions shows that blisters are present in the tight junction before any increase in transepithelial water net flux. This indicates that the two phenomena are dissociated.