Linked Life Data

8169594

Source:http://linkedlifedata.com/resource/pubmed/id/8169594

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-5-27
pubmed:abstractText
The purpose of this study was to characterize excitation-contraction (e-c) coupling in myotubes for comparison with e-c coupling of adult skeletal muscle. The whole cell configuration of the patch clamp technique was used in conjunction with the calcium indicator dye Fluo-3 to study the calcium transients and slow calcium currents elicited by voltage clamp pulses in cultured myotubes obtained from neonatal mice. Cells were held at -80 mV and stimulated with 15-20 ms test depolarizations preceded and followed by voltage steps designed to isolate the slow calcium current. The slow calcium current had a threshold for activation of about 0 mV; the peak amplitude of the current reached a maximum at 30 to 40 mV a and then declined for still stronger depolarizations. The calcium transient had a threshold of about -10 mV, and its amplitude increased as a sigmoidal function of test potential and did not decrease again even for test depolarizations sufficiently strong (> or = 50 mV) that the amplitude of the slow calcium current became very small. Thus, the slow calcium current in myotubes appears to have a negligible role in the process of depolarization-induced release of intracellular calcium and this process in myotubes is essentially like that in adult skeletal muscle. After repolarization, however, the decay of the calcium transient in myotubes was very slow (hundreds of ms) compared to adult muscle, particularly after strong depolarizations that triggered larger calcium transients. Moreover, when cells were repolarized after strong depolarizations, the transient typically continued to increase slowly for up to several tens of ms before the onset of decay. This continued increase after repolarization was abolished by the addition of 5 mM BAPTA to the patch pipette although the rapid depolarization-induced release was not, suggesting that the slow increase might be a regenerative response triggered by the depolarization-induced release of calcium. The addition of either 0.5 mM Cd2+ + 0.1 mM La3+ or the dihydropyridine (+)-PN 200-110 (1 microM) reduced the amplitude of the calcium transient by mechanisms that appeared to be unrelated to the block of current that these agents produce. In the majority of cells, the decay of the transient was accelerated by the addition of the heavy metals or the dihydropyridine, consistent with the idea that the removal system becomes saturated for large calcium releases and becomes more efficient when the size of the release is reduced.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-1082507, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-1660319, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-1711572, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2041724, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-20641, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2157159, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2165571, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2427959, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2434854, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2440542, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2447943, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2447966, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2451745, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2458429, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2482329, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2498308, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2498309, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-2903448, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-3037387, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-3233270, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-3487641, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-3489092, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-4537984, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-6270629, http://linkedlifedata.com/resource/pubmed/commentcorrection/8169594-8246202
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-1295
pubmed:author
pubmed:issnType
Print
pubmed:volume
103
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
107-23
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Measurement of calcium transients and slow calcium current in myotubes.
pubmed:affiliation
Department of Physiology, Colorado State University, Fort Collins 80523.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't