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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1982-12-21
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pubmed:abstractText |
The effects of external Rb+ on the efflux of 42K+ from whole frog sartorius muscles loaded with 305 mM K+ and 120 mM Cl- were studied. K+ efflux is activated by [Rb+]o less than about 40 mM according to a sigmoid relation similar to that for activation by [K+]o. At [Rb+]o greater than 40 mM, K+ efflux declines, although at [Rb+]o = 300 mM it is still greater than at [Rb+]o = 0 mM. For low concentrations, the increment in K+ efflux over that in K+-and Rb+-free solution, delta K, is described by the relation delta k = a[X+]on, for both K+ and Rb+. The value of a is larger for Rb+ than for K+, while the values of n are similar; the activation produced by a given [Rb+]o is larger than that by an equal [K+]o for concentrations less than about 40 mM. Adding a small amount of Rb+ to a K+-containing solution has effects on K+ efflux which depend on [K+]o. At low [K+]o, adding Rb+ increases K+ efflux, the effect being greatest near [K+]o = 30 mM and declining at higher [K+]o; at [K+]o above 40 mM, addition of Rb+ decreases K+ efflux. At [K+]o above 75 mM, where K+ efflux is largely activated, Rb+ reduces K+ efflux by a factor b, described by the relation b = 1/(1+c[Rb+]o). Activation is discussed in terms of binding to at least two sites in the membrane, and the reduction in K+ efflux by Rb+ at high [K+]o in terms of association with an additional inhibitory site.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:issn |
0022-2631
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
69
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
145-57
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:6982343-Animals,
pubmed-meshheading:6982343-Kinetics,
pubmed-meshheading:6982343-Mathematics,
pubmed-meshheading:6982343-Membrane Potentials,
pubmed-meshheading:6982343-Models, Biological,
pubmed-meshheading:6982343-Muscles,
pubmed-meshheading:6982343-Potassium,
pubmed-meshheading:6982343-Rana pipiens,
pubmed-meshheading:6982343-Rubidium,
pubmed-meshheading:6982343-Thermodynamics
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pubmed:year |
1982
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pubmed:articleTitle |
The dual effect of rubidium ions on potassium efflux in depolarized frog skeletal muscle.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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