Salt and Water Transport by Gallbladder Epithelium

Abstract

The sections in this article are: 1 Morphology 2 Basic Transport Functions 3 Mechanisms of Transepithelial Salt Transport 3.1 Basic Electrophysiology of Gallbladder Epithelium 3.2 Paracellular Pathway 3.2.1 Properties of Junctions 3.2.2 Properties of Lateral Intercellular Spaces 3.3 Apical Cell Membrane 3.3.1 Cation Permeability 3.3.2 Anion Permeability 3.4 Basolateral Cell Membrane 3.4.1 Cation Permeability 3.4.2 Anion Permeability 3.5 Intracellular Ionic Activities 3.6 Transepithelial Ion Fluxes 3.7 Mechanisms of Salt Transport at Apical Membrane 3.7.1 Evidence for Apical Membrane Sodium-Hydrogen Exchange 3.7.2 Evidence for Apical Membrane Chloride-Bicarbonate Exchange 3.7.3 Rates of Apical Membrane Ion Exchange 3.7.4 Tests of Independence of Sodium and Chloride Entry 3.8 Mechanisms of Salt Transport at Basolateral Membrane 3.8.1 Sodium Pump 3.8.2 Potassium Channel 3.8.3 Evidence for Potassium Chloride Cotransport 3.8.4 Sodium Recycling 4 Mechanisms of Transepithelial Water Transport 4.1 Pinocytotic Theory 4.2 Electroosmotic Theory 4.3 Osmotic Theory 4.3.1 Cell Membrane Water Permeability 4.3.2 Unstirred Layers 4.3.3 Water Transport Pathway 4.3.4 Driving Force for Osmotic Water Flow 5 Conclusions