Linked Life Data

17485401

Source:http://linkedlifedata.com/resource/pubmed/id/17485401

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2007-5-8
pubmed:abstractText
The aims of this work were to determine: 1) whether Ca2+ exit via the plasmalemmal Ca2+ ATPase (PMCA) is coupled to H+ entry via a Ca2+/H+ exchange; 2) whether operation of PMCA has an absolute requirement on external H+ (Ho); and 3) the stoichiometry and voltage-dependence of the Ca2+/H+ exchange. Barnacle muscle cells were used because of the ease with which they can be internally-perfused (e.g., with 45Ca), voltage-clamped and impaled with a pH electrode. Thus, the simultaneous measurement of plasmalemmal Ca2+ and H+ fluxes can be measured. The effects of Ho, intracellular ATP, PMCA blockers, and membrane potential (VM) were studied on PMCA-mediated Ca2+/H+ exchange. The results indicate that: i) Ca2+ efflux is promoted by external acidification, is accompanied by a membrane depolarization, and by an intracellular acidification greater than the one resulting from Ho "leak" and PMCA-mediated ATP hydrolysis; ii) Ho-dependent Ca2+ efflux is inhibited by PMCA blockers and by ATP depletion and is accelerated by membrane depolarization (~3 fold by 20 mV depolarization); iii) the coupling ratio of the Ca2+/H+ exchange depends on Ho: at an extracellular pH (pHo)=6.5, the ratio is 1Ca2+:~3H+; at pHo=8.2, Ca2+ efflux rate is 3 times slower and the ratio is 1Ca2+: <1H+.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1093-4715
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4641-60
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Ca2+ /H+ exchange via the plasma membrane Ca2+ ATPase in skeletal muscle.
pubmed:affiliation
Dept. Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, N. Chicago, IL 60064, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't