Epithelial Transport

Abstract

The sections in this article are: Transporting Epithelia Are Sheets of Polar Cells Epithelial Structure Involves Specialized Cell–Cell and Cell–Matrix Junctions Epithelial Polarity Is Essential for Vectorial Transport Transporting Epithelia Generate and Maintain Differences in Chemical Composition Between Fluid Compartments Transepithelial Transport Involves Active Ion Transport Passive Transport Processes also Contribute to Transepithelial Transport Transepithelial Transport Involves Transcellular and Paracellular Pathways Chemical and Electrical Gradients Couple Ion Fluxes in Epithelia The Building Blocks of Epithelial Function Are Membrane Transporters Mechanisms of Ion Transport The Two‐Membrane Hypothesis: A General Epithelial‐Transport Model Mechanisms of Transepithelial NaCl Transport in Absorptive Epithelia Mechanisms of Ion Transport in Primary Cl − ‐Transporting Epithelia Mechanisms of Ion Transport in H + — and ‐Transporting Epithelia Mechanisms of Transepithelial Water Transport Transepithelial Water Transport Is Linked to Transepithelial Salt Transport Epithelia Are Widely Diverse in Their Water‐Transport Characteristics Transepithelial Water Transport in Leaky Epithelia Is Nearly Isosmotic Transepithelial Water Transport in Leaky Epithelia Can Be Transcellular and/or Paracellular Water Permeation across Cell Membranes of Some Leaky Epithelia Is via Constitutive Pores Mechanisms of Transepithelial Water Transport in ADH ‐Sensitive Epithelia Molecular Identity of Water Pores in Epithelial‐Cell Membranes Mechanisms of Regulation of Transepithelial Transport Rapid Regulation Long‐term Regulation Intramembrane Regulation and Cross‐Talk Mechanisms

Membrane‐limited expression and regulation of Na+‐H+ exchanger isoforms by P2 receptors in the rat submandibular gland duct

“…The bulk of Na + absorption by CFTR‐expressing and other epithelia is electroneutral and mediated by Na + −H + exchange activity in the LM (Reuss, 1996). Two of the best studied systems are the kidney (Yun et al 1995) and the SMG (Cook et al 1994).…”

DCEBIO stimulates Cl− secretion in the mouse jejunum

“…CFTR is a key Cl Ϫ channel involved in Cl Ϫ secretory response of many epithelial tissues (19,52) and is present in the mouse jejunum (2). Therefore, we tested for the participation of CFTR in the DCEBIO-stimulated I sc response with glibenclamide and NPPB, known blockers of CFTR (10,58,60,73).…”

Models, measurement and inference in epithelial tissue dynamics

“…The epithelial tissues that line the internal and external surfaces of the body are a primary source of physical protection and act as barriers to unwarranted substances [47]. Maintenance of normal physiological function requires that many epithelia simultaneously carry out directed transport of substances such as water and electrolytes between bathing solutions on either side of the epithelial tissue; this is crucial for tasks such as regulating body fluid composition and absorbing nutrients [69]. As a result, many epithelial tissues, such as the skin and intestinal epithelia, have rapid rates of self-renewal and distinctive structural and functional organisation (see below).…”

“…General structure and function. Epithelial tissues comprise sheets of polarised cells, as well as glandular ingrowths (or crypts) and finger-like protrusions (or villi) formed from these sheets; the arrangement of these layers is maintained by specialised cell-cell and cell-matrix junctions [69] ( Figure 1A). These junctions, especially the tight junctions, are crucial not only for structural integrity of the epithelial layers, but also for maintaining cell polarity and, hence, the ability of epithelial tissues to perform directed transport of solutes and water.…”