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  Ion-selective channels in K562 cells: a patch-clamp analysis

Rettinger, J., & Schwarz, W. (1994). Ion-selective channels in K562 cells: a patch-clamp analysis. Journal of Basic and Clinical Physiology and Pharmacology, 5(1), 27-44.

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 Creators:
Rettinger, Jürgen1, Author           
Schwarz, Wolfgang1, Author           
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1Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Max Planck Society, ou_2068289              

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 Abstract: Four types of ion-selective channels were found by the patch-clamp technique in the human erythroleukemia K562 cells. I) in cell-attached configuration at potentials less negative than -40 mV an 8 ps channel was detected. The potential dependence of channel activity suggests that this is the TTX-sensitive Na+ channel. II) A cation-selective channel was observed with equal permeability for Na+ and K+ and a potential-independent single-channel conductance of 19 pS. The channel is activated by intracellular Ca2+ and inhibited by TEA, III) A predominantly anion-selective channel was identified with the selectivity sequence NO3- > J- > Cl- = Br- >> SO42-. The single-channel conductance shows outward rectification, and is in symmetrical NaCl solution 19 pS at -60 mV and 54pS at +50 mV. The open- and closed-time distributions suggest one open and at least four closed states. At submicromolar concentrations, the open state is blocked by H2DIDS leading to channel flicker between open and blocked channel; higher concentrations (apparent KI = 6.8 uM) lead to a longer-lasting blocked state. Both components of inhibition are reversible. IV) In addition, an 8 pS, Na+- and K+- selective channel could be induced by application of palytoxin. For channel activity, the presence of extracellular Na+ is essential. It is assumed that the Na+, K+-pump molecule is involved in the channel formation. Similarly, it is discussed whether the anion-selective channel represents a pore conformation of an electrically silent anion exchanger.

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Language(s): eng - English
 Dates: 1994-01-01
 Publication Status: Published in print
 Pages: 17
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: PMID: 8736069
 Degree: -

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Title: Journal of Basic and Clinical Physiology and Pharmacology
  Abbreviation : J Basic Clin Physiol Pharmacol
Source Genre: Journal
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Publ. Info: London, England : Freund Pub. House, c1990
Pages: - Volume / Issue: 5 (1) Sequence Number: - Start / End Page: 27 - 44 Identifier: ISSN: 0792-6855
ISSN: 2191-0286