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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1978-9-29
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pubmed:abstractText |
The operation of the sodium pump of giant axons of the squid, Loligo pealei, has been studied simultaneously in two independent ways: 1) by measuring sodium efflux with 22Na, and 2) by calculating the transmembrane current generated by the pump from measurements of membrane resistance and digitalis-sensitive membrane potential. In normal, untreated axons, the effect of increasing the external potassium concentration on both sodium efflux and pump current is similar, which suggests that Na:K pump stoichiometry remains relatively constant in the range of 0-20 mM external K. The data are compatible with a 3:2 Na:K ratio. In axons whose intracellular ADP level has been elevated by injection of L-arginine, a large, electrically silent, cardiotonic steroid-sensitive sodium efflux takes place in the absence of external potassium; this suggests that pump-mediated Na:Na exchange is 1:1 or electroneutral. Finally, elevation of external potassium levels causes the appearance, in high-ADP axons, of electrogenic pumping, with little effect on sodium efflux; hence, in contrast to what is seen in normal (low-ADP) axons, the charge translocated, per sodium ion extruded, increases sharply with increasing extracellular potassium levels.
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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:month |
Jul
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pubmed:issn |
0002-9513
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
235
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
C63-8
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:677302-Adenosine Diphosphate,
pubmed-meshheading:677302-Animals,
pubmed-meshheading:677302-Axons,
pubmed-meshheading:677302-Biological Transport, Active,
pubmed-meshheading:677302-Decapodiformes,
pubmed-meshheading:677302-Digitoxigenin,
pubmed-meshheading:677302-Membrane Potentials,
pubmed-meshheading:677302-Potassium,
pubmed-meshheading:677302-Sodium
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pubmed:year |
1978
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pubmed:articleTitle |
Electric current generated by squid giant axon sodium pump: external K and internal ADP effects.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.
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