The proposed studies are part of a continuing investigation of the cellualar mechanisms underlying the transport of water, ions, and water soluble non-electrolytes across the epithelial cell layer of the small intestine and other epithelia. Specifically, the investigation is concerned with the kinetics, energetics, and electrophysiology of ionic absorption and secretion by these tissues. Coupling between ionic transfer processes (e.g., sodium and chloride transport) and between these processes and the transport of organic solutes (e.g., sugars, amino-acids and oligopeptides) is a major concern within the overall scope of the project. Techniques employed include the measurement of transepithelial potential difference, short circuit current, and mucosal membrane potentials in epithelial cells; determination by flame photometry of mucosal sodium and potassium concentrations; measurement of mucosal chloride concentration by electrometric titration, direct determination (with ion-selective microelectrodes) of intracellular ionic activities, and measurement, by radiotracer techniques, of transepithelial and transmucosal fluxes of ions, sugars and amino acids. Because of their exceptional stability in vitro and their functional resemblance to corresponding mammalian tissues, amphibian (bullfrog and necturus) small intestine and gallbladder are used as major exprimental models. The overall goal of this investigation is to provide experimental information and generate functional models that will be of use in the management and control of human disorders arising from intestinal malfunction.
| Armstrong, W M; Lyall, V; Corcia, A et al. (1988) Rheogenic transport of basic and acidic amino acids across the brush border of Necturus small intestine. Prog Clin Biol Res 258:43-65 |
| Acevedo, M; Armstrong, W M (1987) Electrophysiology of L-lysine entry across the brush-border membrane of Necturus intestine. Biochim Biophys Acta 896:295-304 |
| Lyall, V; Croxton, T L; Armstrong, W M (1987) Measurement of intracellular chloride activity in mouse liver slices with microelectrodes. Biochim Biophys Acta 903:56-67 |
| Chao, A C; Armstrong, W M (1987) Cl(-)-selective microelectrodes: sensitivity to anionic Cl- transport inhibitors. Am J Physiol 253:C343-7 |
| Zeldin, D C; Corcia, A; Armstrong, W M (1985) Cyclic AMP-induced changes in membrane conductance of Necturus gallbladder epithelial cells. J Membr Biol 84:193-206 |
