| Altered responsiveness of hypertrophied rat hearts to alpha- and beta-adrenergic stimulation. | |
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MedLine Citation:
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PMID: 1674756 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Inotropic responsiveness to alpha- and beta-adrenergic agents was examined in pressure-overload hypertrophied rat hearts. Pressure overload was induced in rats by abdominal aortic constriction. Three weeks post-constriction, hearts were isolated and perfused with buffer containing various concentrations of (1) calcium (2) isoproterenol (3) forskolin, or (4) phenylephrine. The change in rate of left ventricular pressure development (delta + dP/dt) with increasing perfusate calcium concentrations was comparable in hypertrophied hearts of aortic-constricted rats (AC) and hearts of sham-operated rats (SO). However, with isoproterenol or forskolin stimulation, inotropic responsiveness (delta + dP/dt) was 50% lower in hypertrophied hearts of AC. This was associated with significantly lower tissue cAMP levels. Beta-adrenoceptor number and affinity were unchanged in the hypertrophied myocardium. Maximum inotropic responsiveness to phenylephrine was also lower in hypertrophied hearts and was associated with reduced alpha-adrenoceptor numbers. The data suggest that altered inotropic responsiveness to alpha-adrenergic stimulation may, in part, be due to reduced cardiac alpha-adrenoceptor density. However, post-receptor mechanisms including alterations in cAMP metabolism may contribute to the reduced responsiveness to beta-adrenergic stimulation in hypertrophied hearts of AC. |
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Authors:
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K A Foster; C E Hock; D K Reibel |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of molecular and cellular cardiology Volume: 23 ISSN: 0022-2828 ISO Abbreviation: J. Mol. Cell. Cardiol. Publication Date: 1991 Jan |
Date Detail:
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Created Date: 1991-07-03 Completed Date: 1991-07-03 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0262322 Medline TA: J Mol Cell Cardiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 91-101 Citation Subset: IM |
Affiliation:
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Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic alpha-Agonists
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pharmacology* Adrenergic beta-Agonists / pharmacology* Animals Blood Pressure / drug effects Calcium / pharmacology Cardiomegaly / pathology, physiopathology* Forskolin / pharmacology Isoproterenol / pharmacology Male Myocardial Contraction / drug effects* Myocardium / pathology, ultrastructure Organ Size / drug effects Phenylephrine / pharmacology Rats Rats, Inbred Strains Receptors, Adrenergic, alpha / physiology Receptors, Adrenergic, beta / physiology |
| Grant Support | |
ID/Acronym/Agency:
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HL 30945/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Agonists; 0/Adrenergic beta-Agonists; 0/Receptors, Adrenergic, alpha; 0/Receptors, Adrenergic, beta; 59-42-7/Phenylephrine; 66428-89-5/Forskolin; 7440-70-2/Calcium; 7683-59-2/Isoproterenol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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