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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6 Pt 1
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pubmed:dateCreated |
1995-1-31
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pubmed:abstractText |
Ratiometric fura 2 fluorescence techniques were used to investigate the sources of Ca2+ that lead to an increase in cytosolic Ca2+ concentration ([Ca2+]i) and the generation of force during cholinergic stimulation of canine colonic circular smooth muscle tissues. Acetylcholine (ACh; 1 microM) caused a biphasic increase in [Ca2+]i and force. The initial upstroke phase was characterized by an increase in [Ca2+]i and a pronounced increase in force. The sustained phase was characterized by concurrent oscillations in [Ca2+]i and force (2-3/min) that persisted as long as ACh was present. The increase in [Ca2+]i in response to ACh was reduced to approximately 30% in the presence of nicardipine (1 microM), suggesting that L-type Ca2+ channels contribute to the rise in [Ca2+]i but that other sources also contribute. Preincubation in caffeine (10 mM) and ryanodine (10 microM) reduced the upstroke phase of the increase in [Ca2+]i and contractile responses to ACh, indicating that release of Ca2+ from intracellular stores contributes only to the initial cholinergic response. Responses to ACh persisted when nicardipine (1 microM) was included after emptying of caffeine-ryanodine-sensitive stores, suggesting the presence of additional sources of Ca2+. Data suggest that cholinergic regulation of [Ca2+]i in colonic smooth muscle occurs by a number of parallel pathways. Influx through voltage-dependent Ca2+ channels, release of Ca2+ from intracellular stores, and possibly Ca2+ entry through additional conductances activated by ACh all contribute to the regulation of [Ca2+]i.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Acetylcholine,
http://linkedlifedata.com/resource/pubmed/chemical/Caffeine,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Nicardipine,
http://linkedlifedata.com/resource/pubmed/chemical/Ryanodine
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pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0002-9513
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
267
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
C1666-73
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:7810609-Acetylcholine,
pubmed-meshheading:7810609-Animals,
pubmed-meshheading:7810609-Caffeine,
pubmed-meshheading:7810609-Calcium,
pubmed-meshheading:7810609-Colon,
pubmed-meshheading:7810609-Dogs,
pubmed-meshheading:7810609-Female,
pubmed-meshheading:7810609-Male,
pubmed-meshheading:7810609-Muscle, Smooth,
pubmed-meshheading:7810609-Muscle Contraction,
pubmed-meshheading:7810609-Nicardipine,
pubmed-meshheading:7810609-Ryanodine
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pubmed:year |
1994
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pubmed:articleTitle |
Sources of calcium utilized in cholinergic responses in canine colonic smooth muscle.
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pubmed:affiliation |
Department of Physiology, University of Nevada School of Medicine, Reno 89557.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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