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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1979-3-28
pubmed:abstractText
beta-Adrenoceptor agonists increase myocardial ischemic injury, mainly by elevating myocardial oxygen consumption. Moreover, it has been shown that isoprenaline may "steal" regional myocardial blood flow (RMBF) from ischemic to non ischemic areas and from epicardium to endocardium. The mechanisms of these two isoprenaline-induced redistributions of RMBF have been investigated by the use of radioactive microspheres in an experimental model of canine myocardial ischemia with simultaneous measurement of ST-segment elevation. Isoprenaline increased RMBF in both epi- and endocardial non ischemic areas and in epicardial ischemic areas, leading to a significant decrease in the endo/epi ratio. After atenolol, isoprenaline still increased RMBF but to a lesser extent and the endo/epi ratio was still decreased. Salbutamol, in doses inducing no significant changes in cardiac parameters or myocardial oxygen consumption, produced effects similar to those of isoprenaline. These results indicate a non-homogeneous beta2-stimulation-induced vasodilation in endo- and epicardium, which might be due either to the higher epicardial coronary vasocilatory reserve or to a heterogeneous distribution of transmural beta2-adrenoceptors. Isoprenaline also decreased the ischemic/non ischemic total blood flow ratio (I/NI) and caused further increases in ST-segment elevation. These effects were abolished by atenolol pretreatment, indicating the deleterious effects of isoprenaline-induced tachycardia in this I/NI decrease and in the ischemic injury.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
261-71
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
The role of beta-adrenoceptors in coronary blood flow distribution in normal and ischemic canine myocardium.
pubmed:publicationType
Journal Article