| Ouabain-induced coronary vasoconstriction in cats is not neurally mediated. | |
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MedLine Citation:
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PMID: 11422216 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. Previous reports indirectly implicate a neural mechanism for coronary constriction to centrally administered digitalis. However, autoregulatory changes in coronary resistance due to changes in arterial pressure may have influenced the interpretation of these studies. 2. We tested directly the hypothesis that cardiac sympathetic innervation is responsible for coronary constriction to ouabain by examining the effects of ouabain (intravenous (i.v.) and intracerebroventricular (i.c.v.)) before and after bilateral stellate ganglionectomy. 3. Cats were anaesthetized and instrumented for the measurement of heart rate, blood pressure and coronary blood flow velocity using an epicardial-attached suction Doppler probe. Animals were treated with atenolol and the effects of either i.v. or i.c.v. injections of ouabain were examined. 4. In seven cats treated with atenolol, i.v. ouabain (0.11 mg/kg) produced maximal increases in arterial pressure and coronary vascular resistance index (CVRI) of 66 +/- 7 mmHg and 37 +/- 9%, respectively. Following bilateral stellate ganglionectomy (n = 7), ouabain produced similar increases in arterial pressure (70 +/- 9 mmHg) and CVRI (39 +/- 7%). A higher dose of i.v. ouabain (1.1 mg/kg) produced maximal increases in arterial pressure (115 +/- 4 mmHg) and coronary resistance (86 +/- 14%) in intact cats (n = 6) that were similar to responses seen in cats in which stellate ganglionectomy had been performed (n = 6; arterial pressure 104 +/- 13 mmHg; coronary resistance 114 +/- 6%). The increases in coronary resistance to ouabain at both doses were significantly greater than increases in coronary resistance to passive elevation of arterial pressure during aortic constriction. Thus, autoregulation does not explain fully the coronary constriction to ouabain. 5. To further examine a central mechanism, i.c.v. perfusion with 0.3 mmol/L ouabain was performed in six cats, resulting in increases in arterial pressure (122 +/- 7 mmHg) and coronary resistance (58 +/- 14%). Similar increases in arterial pressure (117 +/- 16%) and coronary resistance (84 +/- 20%) were seen in separate studies (n = 6) following stellate ganglionectomy. 6. These results indicate that coronary constriction to ouabain does not require intact cardiac sympathetic innervation, but probably involves a direct or humorally mediated effect. |
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Authors:
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B A Nair; Y Z Murad; M J Brody; D D Gutterman |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Clinical and experimental pharmacology & physiology Volume: 28 ISSN: 0305-1870 ISO Abbreviation: Clin. Exp. Pharmacol. Physiol. Publication Date: 2001 Jul |
Date Detail:
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Created Date: 2001-06-25 Completed Date: 2001-09-20 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0425076 Medline TA: Clin Exp Pharmacol Physiol Country: Australia |
Other Details:
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Languages: eng Pagination: 510-7 Citation Subset: IM |
Affiliation:
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VA Medical Center, University of Iowa College of Medicine, Iowa City, IA 53226, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Flow Velocity / drug effects Blood Pressure / drug effects Cardiotonic Agents / administration & dosage, pharmacology* Cats Coronary Vessels / drug effects* Ganglionectomy Heart / innervation* Heart Rate / drug effects Injections, Intravenous Injections, Intraventricular Ouabain / administration & dosage, pharmacology* Stellate Ganglion Sympathetic Nervous System* Vascular Resistance / drug effects Vasoconstriction / drug effects* |
| Grant Support | |
ID/Acronym/Agency:
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HL32295-07/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Cardiotonic Agents; 630-60-4/Ouabain |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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