Linked Life Data

15306542

Source:http://linkedlifedata.com/resource/pubmed/id/15306542

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-11-4
pubmed:abstractText
Ca(2+) sparks are highly localized Ca(2+) transients caused by Ca(2+) release from sarcoplasmic reticulum through ryanodine receptors (RyR). In smooth muscle, Ca(2+) sparks activate nearby large-conductance, Ca(2+)-sensitive K(+) (BK) channels to generate spontaneous transient outward currents (STOC). The properties of individual sites that give rise to Ca(2+) sparks have not been examined systematically. We have characterized individual sites in amphibian gastric smooth muscle cells with simultaneous high-speed imaging of Ca(2+) sparks using wide-field digital microscopy and patch-clamp recording of STOC in whole cell mode. We used a signal mass approach to measure the total Ca(2+) released at a site and to estimate the Ca(2+) current flowing through RyR [I(Ca(spark))]. The variance between spark sites was significantly greater than the intrasite variance for the following parameters: Ca(2+) signal mass, I(Ca(spark)), STOC amplitude, and 5-ms isochronic STOC amplitude. Sites that failed to generate STOC did so consistently, while those at the remaining sites generated STOC without failure, allowing the sites to be divided into STOC-generating and STOC-less sites. We also determined the average number of spark sites, which was 42/cell at a minimum and more likely on the order of at least 400/cell. We conclude that 1) spark sites differ in the number of RyR, BK channels, and coupling ratio of RyR-BK channels, and 2) there are numerous Ca(2+) spark-generating sites in smooth muscle cells. The implications of these findings for the organization of the spark microdomain are explored.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0363-6143
pubmed:author
pubmed:issnType
Print
pubmed:volume
287
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C1577-88
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Ca(2+) spark sites in smooth muscle cells are numerous and differ in number of ryanodine receptors, large-conductance K(+) channels, and coupling ratio between them.
pubmed:affiliation
Department of Physiology, University of Massachusetts Medical Center, 55 Lake Ave. North, Worcester, MA 01655, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't