Linked Life Data

7685254

Source:http://linkedlifedata.com/resource/pubmed/id/7685254

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1993-7-12
pubmed:abstractText
Acetylcholine (Ach) activates the muscarinic K+ current in atrial cells via the inhibitory GTP binding protein. After activation, the whole-cell K+ current decreases rapidly (rapid desensitization) to approximately half of the initial current within approximately 20 seconds. The mechanism of this rapid desensitization was investigated in adult rat and guinea pig atrial cells. Whole-cell voltage-clamp and patch-clamp techniques were used to study the K+ current. In voltage-clamped whole cells, ACh activated a K+ current that desensitized rapidly during the initial approximately 20 seconds followed by a slower decrease over several minutes. The rapid K+ current desensitization (a rapid decrease in channel open probability) was also observed at the single-channel level in cell-attached patches and was associated with a progressive shortening of the channel open time and prolongation of the closed time. These changes in channel current and kinetics were abolished by removal of the cytoplasm (by forming inside-out patches) and were partially inhibited by phosphatase inhibitors, suggesting an involvement of cytosolic phosphatase(s) in K+ current desensitization. In inside-out patches with ACh in the pipette and GTP in the bath, the open time of muscarinic K+ channels and channel open probability were increased by 1 mM Mg(2+)-ATP (but not by the nonhydrolyzable analogue, adenylylimidodiphosphate) and decreased by alkaline phosphatase. These results suggest that the rapid K+ current desensitization in adult rat or guinea pig atrial cells is produced by changes in the gating kinetics of the K+ channel, possibly mediated via membrane-associated protein kinase and cytosolic phosphatase(s).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0009-7330
pubmed:author
pubmed:issnType
Print
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
89-97
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Mechanism of rapid desensitization of muscarinic K+ current in adult rat and guinea pig atrial cells.
pubmed:affiliation
Department of Physiology and Biophysics, Chicago Medical School, Ill. 60064.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't