Linked Life Data

8006954

Source:http://linkedlifedata.com/resource/pubmed/id/8006954

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1994-7-19
pubmed:abstractText
Membrane potential changes accompanying Ca2+ influx stimulated by release of Ca2+ from intracellular stores (store-regulated Ca2+ uptake) were monitored in BAPTA-loaded rat thymic lymphocytes using the fluorescent indicator bis(1,3-diethylthiobarbituric acid)trimethine oxonol. Depletion of [Ca2+]i stores by the application of thapsigargin, ionomycin or cyclopiazonic acid induced a depolarization which was (i) dependent upon BAPTA-loading, (ii) dependent upon extracellular Ca2+, (iii) independent of extracellular Na+ and (iv) abolished by 5 mM extracellular Ni2+. This depolarization was followed by a charybdotoxin-sensitive repolarization and subsequent hyperpolarization to values approximating the K+ equilibrium potential, consistent with secondary activation of a K+ conductance. These membrane potential changes temporally correlated with Ca2+ influx from the extracellular medium as measured fluorimetrically with indo-1. The divalent cation permeability sequence was investigated by monitoring the magnitude of the depolarization observed following the addition of 4 mM Ca2+, Mn2+, Ba2+ or Sr2+ to cells pretreated with doses of thapsigargin or ionomycin known to activate the store-regulated calcium uptake pathway. On the basis of these experiments, we conclude that the store-regulated Ca2+ uptake pathway has the following permeability sequence: Ca2+ > Mn2+ >> Ba2+, Sr2+ with Mn2+ displaying significant permeability relative to Ca2+. This pathway is distinguishable from other divalent cation uptake pathways reported in other cells types on the basis of its activation by thapsigargin and its high Mn2+ permeability.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2631
pubmed:author
pubmed:issnType
Print
pubmed:volume
137
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
159-68
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Isolation and characterization of membrane potential changes associated with release of calcium from intracellular stores in rat thymic lymphocytes.
pubmed:affiliation
Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't