| Imidazoline receptors in the heart: characterization, distribution, and regulation. | |
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MedLine Citation:
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PMID: 12021582 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Imidazoline receptors were identified in cardiac tissues of various species. Imidazoline receptors were immunolocalized in the rat heart. Membrane binding and autoradiography on frozen heart sections using 0.5 nM para-iodoclonidine (125I-PIC) revealed that binding was equally and concentration-dependently inhibited by epinephrine and imidazole-4-acetic acid (IAA), implying 125I-PIC binding to cardiac alpha2-adrenergic and I1-receptors, respectively. After irreversible blockade of alpha2-adrenergic receptors, binding was inhibited by the selective I1-agonist, moxonidine, and the I1-antagonist, efaroxan, in a concentration-dependent (10-12 to 10-5 M) manner. Calculation of kinetic parameters revealed that in canine left and right atria, I1-receptor Bmax was 13.4 +/- 1.7 and 20.1 +/- 3.0 fmol/mg protein, respectively. Compared to age-matched normotensive Wistar Kyoto rats, I1-receptors were increased in 12-week-old hypertensive rat (SHR) right (22.6 +/- 0.3 to 43.7 +/- 4.4 fmol/unit area, p < 0.01) and left atria (13.3 +/- 0.6 to 30.2 +/- 4.1 fmol/unit area, p < 0.01). Also, compared to corresponding normal controls, Bmax was increased in hearts of hamsters with advanced cardiomyopathy (13.9 +/- 0.4 to. 26.0 +/- 2.3 fmol/unit area, p < 0.01) and in human ventricles with heart failure (12.6 +/- 1.3 to 35.5 +/- 2.9 fmol/mg protein, p < 0.003). These studies demonstrate that the heart possesses imidazoline I1-receptors that are up-regulated in the presence of hypertension or heart failure, which would suggest their involvement in cardiovascular regulation. |
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Authors:
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Rouwayda El-Ayoubi; Jolanta Gutkowska; Soundar Regunathan; Suhayla Mukaddam-Daher |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of cardiovascular pharmacology Volume: 39 ISSN: 0160-2446 ISO Abbreviation: J. Cardiovasc. Pharmacol. Publication Date: 2002 Jun |
Date Detail:
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Created Date: 2002-05-21 Completed Date: 2002-10-24 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 7902492 Medline TA: J Cardiovasc Pharmacol Country: United States |
Other Details:
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Languages: eng Pagination: 875-83 Citation Subset: IM |
Affiliation:
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Laboratory of Cardiovascular Biochemistry, Center Hospitalier de L'Université de Montréal Research Center, Campus Hotel-Dieu, Quebec, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cardiomyopathies / metabolism Cricetinae Dogs Humans Imidazoline Receptors Mesocricetus Myocardium / chemistry, metabolism* Organ Specificity Rats Rats, Inbred SHR Rats, Inbred WKY Receptors, Drug / analysis, metabolism* Sheep |
| Chemical | |
Reg. No./Substance:
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0/Imidazoline Receptors; 0/Receptors, Drug |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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