| Simulated microgravity increases myogenic tone in rat cerebral arteries. | |
MedLine Citation:
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PMID: 9804560 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Adaptation of the cerebral circulation to microgravity was investigated in rat middle cerebral arteries after 20 days of hindlimb unweighting (HU). Myogenic responses were measured in isolated, pressurized arteries from HU and control animals. Maximal passive lumen diameters, obtained in the absence of extracellular Ca2+ plus EDTA, were not significantly different between groups (249 vs. 258 micrometer). In physiological salt solution, arteries from both HU and control animals maintained a constant lumen diameter when subjected to incremental increases in transmural pressure (20-80 mmHg). However, the diameter of arteries from HU animals was significantly smaller than that of arteries from control animals at all pressures; this difference could be eliminated by exposure to the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester. After HU treatment, transient distensibility of the artery wall in response to pressure was also significantly decreased, whereas the frequency and amplitude of vasomotion were increased. The latter changes were not affected by NG-nitro-L-arginine methyl ester. Thus simulated microgravity increases cerebral artery myogenic tone through both nitric oxide synthase-dependent and -independent mechanisms. |
Authors:
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G G Geary; D N Krause; R E Purdy; S P Duckles |
Publication Detail:
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Type: In Vitro; Journal Article; 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: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 85 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1998 Nov |
Date Detail:
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Created Date: 1998-12-29 Completed Date: 1998-12-29 Revised Date: 2013-09-26 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol (1985) Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1615-21 Citation Subset: IM; S |
Affiliation:
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Department of Pharmacology, College of Medicine, University of California, Irvine, California 92697-4625, USA. gggeary@uci.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / physiology Cerebral Arteries / physiology* Enzyme Inhibitors / pharmacology Hindlimb Suspension Male Muscle Contraction / physiology Muscle Tonus / physiology Muscle, Smooth, Vascular / physiology* NG-Nitroarginine Methyl Ester / pharmacology Nitric Oxide / physiology Nitric Oxide Synthase / antagonists & inhibitors Rats Rats, Wistar Weightlessness Simulation / adverse effects* |
| Grant Support | |
ID/Acronym/Agency:
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R01 HL-50775/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Enzyme Inhibitors; 10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester; 7440-70-2/Calcium; EC 1.14.13.39/Nitric Oxide Synthase |
| Investigator | |
Investigator/Affiliation:
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R E Purdy / U CA, Irvine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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