Linked Life Data

1178069

Source:http://linkedlifedata.com/resource/pubmed/id/1178069

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1976-1-2
pubmed:abstractText
A pattern analysis of inotropic actions was carried out on isotonically chortening cat papillary muscles exposed to (+/-)-verapamil and (+/-)-D 600 and compared to other Ca-antagonistic interventions. 1. (+/-)-Verapamil (1--5mug/ml) leaves contraction amplitudes nearly unchanged at 6/min, whereas at 60/min more than 90% depression (5 mug/ml) occurs. (+/-)-D 600 is about twice as effective as (+/-)-berapamil. 2. An increase of [Ca2+]O in the presence of (+/-)-verapamil or (+/-)-D 600 does not restitute the normal amplitude-frequency relationship. There is only a shift toward higher contraction amplitudes. 3. (+/-)-Verapamil and (+/-)-D 600 lead to typical biphasic inotropic transients after step changes of the friving rhythm. First a fast and (at higher frequencies) very pronounced negative staircase occurs, followed by a rather slowly developing positive staircase. 4. These drug effects contrast to the effects of lowering [Ca2+]O or of adding Ni2+ or La3+, which all produce a rather uniform depression of contraction amplitudes at all frequencies and do not elicit staircase phenomena such as seen under the influence of (+/-)-verapamil or (+/-)-D 600. 5. In contrast to the action of Ni2+, La3+ or low [Ca2+]O, (+/-)-verapamil slows down the restitution kinetics of Ca-reavailability from internal stores as determined by the amplitude of test contractions elicited after various periods of rest. 6. Drug-induced changes in the time course of the transmembrane action potential as depending on frequency may partially but not fully explain the contractile phenomena. 7. Possible interpretations as to the sites where (+/-)-verapamil or (+/-)-D 600 interferes with cardiac excitation-contraction coupling are given by the aid of a multicompartment model. This model describes excitation-contraction coupling in terms of transmembrane and intracellular Ca-movements.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0028-1298
pubmed:author
pubmed:issnType
Print
pubmed:volume
290
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49-68
pubmed:dateRevised
2010-3-12
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Inotropic and electrophysiological actions of verapamil and D 600 in mammalian myocardium. I. Pattern of inotropic effects of the racemic compounds.
pubmed:publicationType
Journal Article, Comparative Study