Linked Life Data

11698234

Source:http://linkedlifedata.com/resource/pubmed/id/11698234

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2001-11-7
pubmed:abstractText
The goal of the present study was to test the hypothesis that local Ca(2+) release events (Ca(2+) sparks) deliver high local Ca(2+) concentration to activate nearby Ca(2+)-sensitive K(+) (BK) channels in the cell membrane of arterial smooth muscle cells. Ca(2+) sparks and BK channels were examined in isolated myocytes from rat cerebral arteries with laser scanning confocal microscopy and patch-clamp techniques. BK channels had an apparent dissociation constant for Ca(2+) of 19 microM and a Hill coefficient of 2.9 at -40 mV. At near-physiological intracellular Ca(2+) concentration ([Ca(2+)](i); 100 nM) and membrane potential (-40 mV), the open probability of a single BK channel was low (1.2 x 10(-6)). A Ca(2+) spark increased BK channel activity to 18. Assuming that 1-100% of the BK channels are activated by a single Ca(2+) spark, BK channel activity increases 6 x 10(5)-fold to 6 x 10(3)-fold, which corresponds to approximately 30 microM to 4 microM spark Ca(2+) concentration. 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester caused the disappearance of all Ca(2+) sparks while leaving the transient BK currents unchanged. Our results support the idea that Ca(2+) spark sites are in close proximity to the BK channels and that local [Ca(2+)](i) reaches micromolar levels to activate BK channels.
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
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C1769-75
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Micromolar Ca(2+) from sparks activates Ca(2+)-sensitive K(+) channels in rat cerebral artery smooth muscle.
pubmed:affiliation
Department of Pharmacology, University of Vermont, Burlington, Vermont 05405, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't