| Effect of tolerance to glyceryl trinitrate on vascular responses in conscious rabbits. | |
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MedLine Citation:
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PMID: 1914247 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. The effect of tolerance to glyceryl trinitrate (GTN) on vasodilator and vasoconstrictor responses was examined in conscious rabbits and isolated rabbit aortic rings. 2. In conscious rabbits, depressor responses to 5 min infusions of GTN (10-40 micrograms/kg per min intravenously (i.v.)), sodium nitroprusside (SNP, 5-20 micrograms/kg per min i.v.) and acetylcholine (ACh, 3-12 micrograms/kg per min i.v.) were examined before and after transdermal treatment with GTN (20 mg/48 h). GTN pretreatment significantly attenuated GTN-induced depressor responses, indicating the development of tolerance, but did not affect the reductions in arterial pressure induced by SNP or ACh. 3. Similarly, aortic rings taken from GTN pretreated rabbits exhibited tolerance to GTN but the relaxant responses to SNP or the calcium ionophore A23187 were not affected. In the aortic rings from GTN-tolerant rabbits contractile responses to serotonin or the thromboxane-mimetic U46619 were significantly attenuated, in contrast to the responses to the alpha 1-adrenoceptor agonist phenylephrine (PE) which were significantly enhanced. 4. Similarly, in conscious rabbits, PE-induced increases in arterial pressure and hindlimb vascular resistance were significantly enhanced by GTN pretreatment but the responses to the alpha 2-adrenoceptor agonist BHT 920 were unaffected. 5. In conclusion, tolerance to GTN does not affect endothelium-dependent vasodilatation but does cause a selective enhancement of alpha 1- but not alpha 2-adrenoceptor-mediated vasoconstriction. |
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Authors:
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Z Y Du; G J Dusting; O L Woodman |
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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: Clinical and experimental pharmacology & physiology Volume: 18 ISSN: 0305-1870 ISO Abbreviation: Clin. Exp. Pharmacol. Physiol. Publication Date: 1991 Jun |
Date Detail:
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Created Date: 1991-11-08 Completed Date: 1991-11-08 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0425076 Medline TA: Clin Exp Pharmacol Physiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 439-47 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, University of Melbourne, Victoria, Australia. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Administration, Cutaneous Animals Aorta, Thoracic / drug effects*, physiology Consciousness Drug Tolerance / physiology Endothelium, Vascular / drug effects*, physiology Female Hemodynamics / drug effects Male Muscle Contraction / drug effects Muscle Relaxation / drug effects Nitroglycerin / pharmacology* Rabbits Vasoconstrictor Agents / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Vasoconstrictor Agents; 55-63-0/Nitroglycerin |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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