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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
9
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pubmed:dateCreated |
2002-5-1
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pubmed:abstractText |
Stretch-activated channels (SACs) have been found in smooth muscle and are thought to be involved in myogenic responses. Although SACs have been shown to be Ca(2+) permeable when Ca(2+) is the only charge carrier, it has not been clearly demonstrated that significant Ca(2+) passes through SACs in physiological solutions. By imaging at high temporal and spatial resolution the single-channel Ca(2+) fluorescence transient (SCCaFT) arising from Ca(2+) entry through a single SAC opening, we provide direct evidence that significant Ca(2+) can indeed pass through SACs and increase the local [Ca(2+)]. Results were obtained under conditions where the only source of Ca(2+) was the physiological salt solution in the patch pipette containing 2 mM Ca(2+). Single smooth muscle cells were loaded with fluo-3 acetoxymethyl ester, and the fluorescence was recorded by using a wide-field digital imaging microscope while SAC currents were simultaneously recorded from cell-attached patches. Fluorescence increases at the cell-attached patch were clearly visualized before the simultaneous global Ca(2+) increase that occurred because of Ca(2+) influx through voltage-gated Ca(2+) channels when the membrane was depolarized by inward SAC current. From measurements of total fluorescence ("signal mass") we determined that about 18% of the SAC current is carried by Ca(2+) at membrane potentials more negative than the resting level. This would translate into at least a 0.35-pA unitary Ca(2+) current at the resting potential. Such Ca(2+) currents passing through SACs are sufficient to activate large-conductance Ca(2+)-activated K(+) channels and, as shown previously, to trigger Ca(2+) release from intracellular stores.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-10091002,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-10498675,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-10747180,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-11099344,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-11099351,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-11274342,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-11279498,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1285439,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1373561,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1373571,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1415587,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1690807,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-1847010,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2422949,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2436143,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2444891,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2459658,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2466333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-2894775,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-6289042,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-6776818,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-7510889,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-7688583,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-7692040,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-8606791,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-8608860,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-8722560,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-9080360,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/11983921-9925820
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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 |
Apr
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
30
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pubmed:volume |
99
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
6404-9
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:11983921-Animals,
pubmed-meshheading:11983921-Bufo marinus,
pubmed-meshheading:11983921-Calcium,
pubmed-meshheading:11983921-Calcium Channels,
pubmed-meshheading:11983921-Cations,
pubmed-meshheading:11983921-Electrophysiology,
pubmed-meshheading:11983921-Muscle, Smooth,
pubmed-meshheading:11983921-Patch-Clamp Techniques,
pubmed-meshheading:11983921-Spectrometry, Fluorescence,
pubmed-meshheading:11983921-Time Factors
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pubmed:year |
2002
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pubmed:articleTitle |
Visualization of Ca2+ entry through single stretch-activated cation channels.
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pubmed:affiliation |
Department of Physiology and Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, MA 01655, USA. imaging.ionchannels@umassmed.edu
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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