Linked Life Data

8001267

Source:http://linkedlifedata.com/resource/pubmed/id/8001267

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-1-26
pubmed:abstractText
We have investigated the modulation of the L-type Ca2+ channel by Ca2+ released from the sarcoplasmic reticulum (SR) in single guinea pig ventricular myocytes under whole-cell voltage clamp. [Ca2+]i was monitored by fura 2. By use of impermeant monovalent cations in intracellular and extracellular solutions, the current through Na+ channels, K+ channels, nonspecific cation channels, and the Na+-Ca2+ exchanger was effectively blocked. By altering the amount of Ca2+ loading of the SR, the time course of the Ca2+ current (ICa) could be studied during various amplitudes of Ca2+ release. In the presence of a large Ca2+ release, fast inhibition of ICa occurred, whereas on relaxation of [Ca2+]i, fast recovery was observed. The time course of this transient inhibition of ICa reflected the time course of [Ca2+]i. However, the inhibition seen in the first 50 ms, ie, the time of net Ca2+ release from the SR, exceeded the inhibition observed later during the pulse, suggesting the existence of a higher [Ca2+] near the channel during this time. Transient inhibition of ICa during Ca2+ release was observed to a similar degree at all potentials. It could still be observed in the presence of intracellular ATP-gamma-S and of cAMP. Therefore, we conclude that the modulation of ICa by Ca2+ release from the SR is not related to dephosphorylation. It could be related to a reduction in the driving force and to a direct inhibition of the channel by [Ca2+]i. The observation that the degree of inhibition does not depend on membrane potential suggests that the Ca2+ binding site for this modulation is located outside the pore.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0009-7330
pubmed:author
pubmed:issnType
Print
pubmed:volume
76
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
102-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Inhibition and rapid recovery of Ca2+ current during Ca2+ release from sarcoplasmic reticulum in guinea pig ventricular myocytes.
pubmed:affiliation
Laboratory of Physiology, University of Leuven, Belgium.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't