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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
1991-10-4
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| pubmed:abstractText |
1. Single smooth muscle cells from the fundus region of the guinea-pig stomach, which showed contractile responses to acetylcholine (ACh) at concentrations greater than or equal to 10(-7) mol/l, were obtained by enzymatic digestion using highly purified collagenase and papain. They were studied by recording membrane currents under voltage clamp with the patch pipette technique in the whole-cell configuration at 25-28 degrees C. 2. By applying voltage jumps from negative holding levels (-70 to -60 mV) to more positive levels, we identified two major activating currents: an initial inward Ca2+ current (ICa) was followed, and partly overlapped, by an outward K+ current (IK). 3. Cholinergic effects on membrane currents were investigated in the range of negative membrane potentials by determining current-voltage relations in the absence of ACh and during its continuous presence in the bathing fluid. 4. ACh induced a decrease in the steady-state conductance which was reversibly blocked by atropine. At physiological external K+ concentration [( K+]o = 6 mmol/l), the reversal potential (Erev) of the current suppressed by ACh (3 x 10(-6) mol/l) was about 20 mV more positive than the calculated K+ equilibrium potential (EK). 5. When [K+]o was increased, Erev was shifted positively; but at each [K+]o, Erev was more positive than EK. 6. Like ACh (10(-6) mol/l), tetraethylammonium (TEA, 1 mmol/l) also suppressed a current with a reversal potential that was, at physiological [K+]o, 20 mV more positive than EK. ACh (10(-5) mol/l) applied in the presence of 1 mmol/l TEA suppressed a pure K+ current (Erev = EK), which was also suppressed by 10 mmol/l TEA. 7. When K+ in the pipette and in the bathing solution was completely replaced by Na+, both ACh (10(-5) mol/l) and TEA (1 mmol/l) caused a reduction of the membrane conductance that appeared to be identical. TEA added to the bathing solution in the presence of ACh did not produce a significant additional conductance decrease. These results did not depend on whether Cl- was present as a charge carrier or not. 8. It is concluded that in fundus muscle of the guinea-pig stomach a major mechanism underlying muscarinic activation is a decrease of a K+ conductance. In addition the results indicate a suppression of a small Na+ conductance which is made up by a population of channels that are also blocked by TEA.
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| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-18128147,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2409600,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2410793,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2414443,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2417191,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2431323,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2439921,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2442353,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2446250,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2447524,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-2451291,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-3041121,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-3261007,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-37533,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-5016040,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-5461324,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-5500729,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-6270629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-6299445,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-6760380,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-6965523,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-7326323,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1886057-7326324
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jan
|
| pubmed:issn |
0022-3751
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
432
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
259-82
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| pubmed:dateRevised |
2010-9-9
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| pubmed:meshHeading |
pubmed-meshheading:1886057-Acetylcholine,
pubmed-meshheading:1886057-Animals,
pubmed-meshheading:1886057-Calcium,
pubmed-meshheading:1886057-Cells, Cultured,
pubmed-meshheading:1886057-Electrophysiology,
pubmed-meshheading:1886057-Gastric Fundus,
pubmed-meshheading:1886057-Guinea Pigs,
pubmed-meshheading:1886057-Membrane Potentials,
pubmed-meshheading:1886057-Muscle, Smooth,
pubmed-meshheading:1886057-Potassium
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| pubmed:year |
1991
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| pubmed:articleTitle |
Suppression of steady membrane currents by acetylcholine in single smooth muscle cells of the guinea-pig gastric fundus.
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| pubmed:affiliation |
Department of Physiology, Philipps University, Marburg, Germany.
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| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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