These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A simple assay for agonist-regulated Cl and K conductances in salt-secreting epithelial cells.
    Author: Venglarik CJ, Bridges RJ, Frizzell RA.
    Journal: Am J Physiol; 1990 Aug; 259(2 Pt 1):C358-64. PubMed ID: 1696431.
    Abstract:
    We developed a convenient flux assay that permits simultaneous measurement of Cl and K conductance pathways in Cl-secreting epithelial cells. Monolayers of the colonic tumor cell line T84 were preloaded with 125I and 86Rb, and isotope effluxes were monitored by a sample-replace procedure. The adenosine 3',5'-cyclic monophosphate (cAMP)-mediated agonists forskolin and prostaglandin E2 increased I efflux with little effect on Rb efflux, whereas the Ca-mediated agonists ionomycin, A23187, and carbachol increased both I and Rb effluxes. Simultaneous determinations of I and Cl or Rb and K effluxes indicated that I and Rb provide good measures of the effluxes of Cl and K, respectively. Forskolin- and ionomycin-stimulated I effluxes were inhibited by the Cl-channel blockers diphenylamine-2-dicarboxylate (DPC), 5-nitro-2-(3-phenylpropyl-amino)benzoic acid (NPPB), and 2-[cyclopentyl-6,7-dichloro-2,3-dihydro-2-methyl-1-oxo-1H- inden-5-yl)oxy]acetic acid (IAA-94) and by high external K. The Rb efflux evoked by ionomycin was inhibited by the K-channel blockers Ba and charybdotoxin. These findings suggest that I and Rb effluxes provide qualitative estimates of agonist-stimulated Cl and K conductance pathways. Thus this method can provide a simple and relatively inexpensive screening assay for Cl and K conductances in cultured cells to assess the effects of agonist, blockers, or genetic manipulations.
    [Abstract] [Full Text] [Related] [New Search]