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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1995-1-25
|
| pubmed:abstractText |
Small pieces of atrial tissue removed from the cannulation site before cardioplegia were used to develop a method for studying adrenergic regulation of the myocardial contractile force in children operated on for congenital heart defects (CHD). We measured the development of the isometric force of contraction dT/dtmax (T'max). Reduction in basal contractility induced by the beta-adrenoceptor antagonist timolol indicated that the myocardium was about half-maximally stimulated by endogenous norepinephrine (NE), probably released from nerve endings by the electrical stimulation. The inotropic effect of endogenous NE could be further increased by tyramine (EC50 approximately 5 microM). A maximal concentration of tyramine increased T'max by a median of 62.5% above the basal level. Sequential blockade of the beta- and alpha 1-adrenoceptors after tyramine stimulation by timolol and prazosin, respectively, indicated that a near-maximal response to combined adrenoceptor stimulation by endogenous NE was mediated by both beta-adrenoceptors (median 77%) and alpha 1-adrenoceptors (median 23%). The basal level of endogenous NE may conceal inotropic effects by exogenous alpha-agonists added to this type of preparation. This preparation is suitable for studying adrenergic regulation by reversing the effects of endogenous NE.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Norepinephrine,
http://linkedlifedata.com/resource/pubmed/chemical/Prazosin,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, alpha,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, beta,
http://linkedlifedata.com/resource/pubmed/chemical/Timolol,
http://linkedlifedata.com/resource/pubmed/chemical/Tyramine
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Sep
|
| pubmed:issn |
0160-2446
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
24
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
365-71
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:7528291-Adolescent,
pubmed-meshheading:7528291-Atrial Function,
pubmed-meshheading:7528291-Child,
pubmed-meshheading:7528291-Child, Preschool,
pubmed-meshheading:7528291-Dose-Response Relationship, Drug,
pubmed-meshheading:7528291-Electric Stimulation,
pubmed-meshheading:7528291-Female,
pubmed-meshheading:7528291-Heart Atria,
pubmed-meshheading:7528291-Heart Defects, Congenital,
pubmed-meshheading:7528291-Humans,
pubmed-meshheading:7528291-Infant,
pubmed-meshheading:7528291-Infant, Newborn,
pubmed-meshheading:7528291-Male,
pubmed-meshheading:7528291-Myocardial Contraction,
pubmed-meshheading:7528291-Norepinephrine,
pubmed-meshheading:7528291-Prazosin,
pubmed-meshheading:7528291-Receptors, Adrenergic, alpha,
pubmed-meshheading:7528291-Receptors, Adrenergic, beta,
pubmed-meshheading:7528291-Regression Analysis,
pubmed-meshheading:7528291-Time Factors,
pubmed-meshheading:7528291-Timolol,
pubmed-meshheading:7528291-Tyramine
|
| pubmed:year |
1994
|
| pubmed:articleTitle |
Functional characterization of an ex vivo preparation of atrial myocardium from children with congenital heart defects: sensitivity to tyramine and adrenoceptor antagonists.
|
| pubmed:affiliation |
Department of Pharmacology, University of Oslo, Norway.
|
| pubmed:publicationType |
Journal Article,
Clinical Trial,
Research Support, Non-U.S. Gov't
|