Linked Life Data

2757265

Source:http://linkedlifedata.com/resource/pubmed/id/2757265

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1989-8-31
pubmed:abstractText
Direct measurements of free intracellular calcium (Ca)i are needed for an understanding of the regulation of contractility. An on-line measurement of (Ca)i with Ca-selective microelectrodes in intact muscle strips provides a suitable means of investigating this problem, although considerable methodologic difficulties exist. Measurements of (Ca)i concentrations during muscle contraction have been carried out by different methods such as Ca-binding techniques and aequorin luminescence, but remain unsatisfying, since they were not performed on intact muscle strips. The authors' measurements were carried out with Ca-selective microelectrodes on rat papillary muscles (stretched to optimal length in a perfusion bath of 1.54 mL at 30 degrees C). The impalement of electrodes was considered adequate when the heights of Ca-electrode potential and membrane potential remained constant for more than twenty minutes. For provoking contractile responses, the authors replaced the normal Tyrode solution by a caffeine-containing contracture solution (content in mM: 0 NaCl [choline], 4 CaCl2, 30 KCl, 25 caffeine, 1.05 MgCl2). Ca-selective microelectrodes were calibrated before and after each measurement and only those impalements were taken as adequate that showed identical calibration curves before and after the experiment. They measured the (Ca)i at 20%, 50%, and 80% of maximal contractile force and obtained (Ca)i concentrations of 1.1 +/- 0.3 microM (at 20%), 3.6 +/- 1.2 microM (at 50%), and 11.8 +/- 0.27 microM (at 80%) (n = 6, +/- SEM). These results represent the fist on-line measurements of the myocardial (Ca)i concentrations with Ca++-selective microelectrodes in intact muscle strips during various degrees of contraction.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0003-3197
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
736-42
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Free calcium in rat papillary muscle at contraction assessed with Ca-selective microelectrodes.
pubmed:affiliation
Physiological Institute, University of Freiburg, West Germany.
pubmed:publicationType
Journal Article