Competitive membrane adsorption of Na+, K+, and Ca2+ in smooth muscle cells

Michael A. Kolber, Cornelis van Breemen

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

A theory for Na+, K+ and Ca2+ competitive adsorption to a charged membrane is used to explain a number of experimental observations in smooth muscle. Adsorption is described by Langmuir isotherms for mono- and divalent cations which in turn are coupled in a self-consistent way to the bulk solution through the diffuse double layer theory and the Boltzman equations. We found that the dissociation constants for binding of Na+, K+ and Ca2+ in guinea pig taenia coli are ca. 0.009, 1.0, and 4×10-8m, respectively. Furthermore, the effect of a Ca2+ pump that maintains free surface Ca2+ concentration constant is investigated. A decrease in intracellular Na+ content results in an increased Ca2+ uptake; part of this uptake is due to an increase in surface-bound Ca2+ in an intracellular compartment which is in contact with the myofilaments. Variations in the amount of charge available to bind Ca2+ and the surface charge density are studied and their effect interpreted in terms of different pharmacological agents.

Original languageEnglish (US)
Pages (from-to)115-121
Number of pages7
JournalThe Journal of Membrane Biology
Volume58
Issue number2
DOIs
StatePublished - Jun 1 1981

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ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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