Actions of the CI- channel blocker NPPB on absorptive and secretory transport processes of Na+ and CI- in rat descending colon - Research portal of Justus Liebig University Giessen:

Journal article

Actions of the CI- channel blocker NPPB on absorptive and secretory transport processes of Na+ and CI- in rat descending colon

Authors list: Diener, M; Rummel, W

Publication year: 1989

Pages: 215-222

Journal: Acta physiologica Scandinavica

Volume number: 137

Issue number: 2

ISSN: 0001-6772

DOI Link: https://doi.org/10.1111/j.1748-1716.1989.tb08741.x

Publisher: Blackwell

Abstract:
The effects of the Cl- channel blocker, NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate), on the transport of Na+ and Cl- in the descending colon of the rat were studied in the Ussing chamber. In control tissue, NPPB administered at the mucosal side of the epithelium increased the short-circuit current (Isc) and inhibited the unidirectional mucosa-to-serosa fluxes of Na+ and Cl-. In HCO3-- or Cl-free media or in the presence of SITS (4-acetamido-4''-isothiocyanato-stilbene-2,2''-disulphonic acid), this increase in Isc caused by mucosal NPPB was not observed. The serosal administration of NPPB was without effect. Mucosal NPPB (10-4 mol l-1) decreased the forskolin-induced increase in Isc by only about 60%. However, the activation of the serosa-to-mucosa flux of Cl- caused by forskolin was inhibited completely. NPPB decreased the mucosa-to-serosa fluxes of Na+ and Cl- reduced additionally by forskolin. Serosal NPPB decreased Isc and Jsmsm, but had no effect on JmsNa or JmsCl. In HCO3--free buffer the increase in Isc induced by forskolin was inhibited completely by NPPB. The inhibition of Cl- secretion by NPPB fits well with the capacity of the drug to block Cl-channels. For the inhibition of neutral NaCl absorption two sites of action are discussed: an interaction with the Cl-/HCO3- exchanger or an interference with the extrusion of Cl- through the basolateral membrane.

Authors/Editors

- Uni.-Prof. Dr. Martin Heinz Diener

Citation Styles

Harvard Citation style: Diener, M. and Rummel, W. (1989) Actions of the CI- channel blocker NPPB on absorptive and secretory transport processes of Na+ and CI- in rat descending colon, Acta physiologica Scandinavica, 137(2), pp. 215-222. https://doi.org/10.1111/j.1748-1716.1989.tb08741.x

APA Citation style: Diener, M., & Rummel, W. (1989). Actions of the CI- channel blocker NPPB on absorptive and secretory transport processes of Na+ and CI- in rat descending colon. Acta physiologica Scandinavica. 137(2), 215-222. https://doi.org/10.1111/j.1748-1716.1989.tb08741.x