| Alpha 1- and alpha 2-adrenoceptor-mediated vasoconstriction of large and small canine coronary arteries in vivo. | |
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MedLine Citation:
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PMID: 6209507 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The role of alpha-adrenoceptor subtypes mediating vasoconstriction of large epicardial and small resistive coronary arteries was investigated in 26 open-chest dogs. The left circumflex coronary artery was perfused at a constant pressure. Large vessel vasomotion was determined by measurement of circumflex coronary arterial diameter (ultrasonic transit-time technique); the vasomotion of the small resistive coronary arteries was determined from calculated end-diastolic circumflex artery resistance. beta-Receptors were blocked by propranolol (2 mg/kg i.v.) and both vagal nerves were cut. In eight dogs, the intracoronary administration of the alpha 1-adrenoceptor agonist methoxamine (500 micrograms) increased calculated large vessel resistance by 18.8 +/- 5.7% and end-diastolic resistance by 9.5 +/- 0.3%. Intracoronary administration of the alpha 2-adrenoceptor agonist BHT 920 (500 micrograms) did not affect large vessel resistance, but increased end-diastolic resistance by 37.5 +/- 5.6%. In an additional 18 dogs, left cardiac sympathetic nerve stimulation induced an increase in large vessel resistance by 11.1 +/- 0.9% and in end-diastolic resistance by 31.8 +/- 3.0%. The increase in large vessel resistance was prevented by the alpha 1-adrenoceptor antagonist prazosin (1.2 mg/kg i.v.), which still permitted an increase in end-diastolic resistance by 23.0 +/- 3.2%. The increase in end-diastolic resistance was prevented by the alpha 2-adrenoceptor antagonist rauwolscine (0.2 mg/kg i.v.), which still permitted an increase in large vessel resistance by 11.9 +/- 2.4%. The calcium antagonist nifedipine (20 micrograms/kg i.v.) prevented both the increase in large vessel resistance and end-diastolic resistance during sympathetic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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G Heusch; A Deussen; J Schipke; V Thämer |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of cardiovascular pharmacology Volume: 6 ISSN: 0160-2446 ISO Abbreviation: J. Cardiovasc. Pharmacol. Publication Date: 1984 Sep-Oct |
Date Detail:
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Created Date: 1984-12-28 Completed Date: 1984-12-28 Revised Date: 2006-11-15 |
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: 961-8 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Azepines / pharmacology Coronary Vessels / drug effects, physiology* Dogs Electric Stimulation Heart / innervation Methoxamine / pharmacology Nifedipine / pharmacology Prazosin / pharmacology Receptors, Adrenergic, alpha / physiology* Sympathetic Nervous System / physiology Vasoconstriction* / drug effects |
| Chemical | |
Reg. No./Substance:
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0/Azepines; 0/Receptors, Adrenergic, alpha; 19216-56-9/Prazosin; 21829-25-4/Nifedipine; 36085-73-1/talipexole; 390-28-3/Methoxamine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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