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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
1
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pubmed:dateCreated |
1977-1-25
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pubmed:abstractText |
1. A double sucrose-gap voltage-clamp technique has been used to study the effects of acetylcholine on the membrane currents in atrial trabeculae of the bullfrog, Rana catesbeiana. 2. The second, or slow inward (Ca2+/Na+) current, was found to be markedly reduced by concentrations of acetylcholine greater than approximately 2-0 X 10(-8)M. The resulting decrease in net calcium entry provides a straightforward explanation for the negative inotropic action of acetylcholine in atrial muscle. 3. Measurements of membrane resistance near the resting potential showed that relatively high doses of acetylcholine (approximately 10(-7) M) decrease membrane resistance by about twofold. This effect is shown to be the result of an increase in a time-independent background current which appears to be carried mainly by potassium ions. 4. Using appropriate pharmacological techniques, it has been possible to demonstrate: (i) that the peak slow inward current is reduced to about half its initial value before any significant increase in background current occurs; (ii) that even when a sufficient dose of acetylcholine to produce an increase in background current is used, the background current shows inward-going rectification and cannot account for the observed reduction in the slow inward current. 5. No consistent change was observed in the degree of activation of the time-dependent outward membrane currents after application of concentrations of acetylcholine which produced large decreases in the peak slow inward current. 6. These results are discussed in relation to previous electro-physiological and radioisotope studies of the mechanism of the negative inotropic effect of acetylcholine in cardiac muscle.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1079874,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1081140,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1081889,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1082504,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1086355,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1086356,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1086357,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1086358,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-1176946,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13070220,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13319658,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13357742,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13460275,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13553747,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13655238,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-13994011,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-14214414,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-14256442,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-14394097,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-238248,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4405213,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4415829,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4537238,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4541362,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4544319,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4547136,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4575321,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4735612,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4951054,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-4976798,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-5066332,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-5346531,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-5824109,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-5856318,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-5890138,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1086900-943764
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
261
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
103-23
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:1086900-Acetylcholine,
pubmed-meshheading:1086900-Action Potentials,
pubmed-meshheading:1086900-Animals,
pubmed-meshheading:1086900-Atrial Function,
pubmed-meshheading:1086900-Biological Transport, Active,
pubmed-meshheading:1086900-Calcium,
pubmed-meshheading:1086900-Electric Conductivity,
pubmed-meshheading:1086900-Heart Atria,
pubmed-meshheading:1086900-Mathematics,
pubmed-meshheading:1086900-Myocardium,
pubmed-meshheading:1086900-Potassium,
pubmed-meshheading:1086900-Rana catesbeiana,
pubmed-meshheading:1086900-Sodium,
pubmed-meshheading:1086900-Time Factors
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pubmed:year |
1976
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pubmed:articleTitle |
Changes in membrane currents in bullfrog atrium produced by acetylcholine.
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pubmed:publicationType |
Journal Article,
In Vitro
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