Transepithelial fluid transport

The Ussing-Zerahn Model of Transepithelial Fluid Transport... 

In addition to these classic responses, activation of sensory nerves can cause an increase in bronchial blood flow (8), bronchomotor tone (1), mueous secretion (9-12), and ciliary beat frequency (13), and possibly an increase of transepithelial fluid transport (14,15). In concert, these effects on the components of the mucociliary transport system are likely to cause an increase in mucoeiliary... 

Secretory epithelia control transport of water and solutes from the subluminal compartment (blood) into the lumen or body exterior. At present, there is no single unifying model for transepithelial fluid or water transport. In some epithelia, transcellular routes of fluid transport via water channels may predominate [88a], However, in other types of epithelia, such as the cervical-vaginal epithelia, transport of fluids usually occurs via the paracellular route [1, 14], In the latter, movement of fluid can be driven by three main mechanisms (Figure 15.1C) ... 

Periciliary fluid is a watery, ionic solution, maintained by transepithelial ion transport, that provides an environment within which the cilia are able to beat. It also provides a reservoir of fluid for the humidification of inspired air. The depth of the periciliary fluid dictates whether the overlying mucus layer is at the ciliary tips and thus available for clearance ... 

Han D-Y, Nie H-G, Gu X et al (2010) K+ channel openers restore verapamil-inhibited lung fluid resolution and transepithelial ion transport. Respir Res 11 65... 

Epithelia like those of the small intestine, proximal renal tubule, and gall bladder are characterised by low or negligible transepithelial potential, low trans-epithelial resistance, and high hydraulic conductivity, and the shunt conductance is a large fraction of the total transepithelial conductance. These epithelia are able to transport large volumes of isotonic fluid. 

The mechanisms involved in urate reabsorption are not well known. The reabsorptive mechanism in at least a few species represents active transport urate may be reabsorbed from tubular fluid of the Cebus monkey when the concentration of urate is smaller than in the plasma and smaller than that predicted by the transepithelial electrical potential difference at equilibrium. Furthermore, in man and the chimpanzee, the concentration of urate in urine becomes smaller than that in the plasma when the secretion of urate is inhibited by the administration of pyrazinoic or pyrazinamide (Roch-Ramel and Weiner, 1980, review). 

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