Abstract
The effects of acute exercise on receptor-mediated endothelium-dependent vasodilation and its possible mechanisms were investigated in the presence of indomethacin. Male Wistar rats (16-20 weeks old) were divided into control and exercise groups. The exercise group ran on a drum exerciser until exhaustion, followed by immediate decapitation. Acetylcholine (ACh)- or clonidine (CLO)-induced vasodilating responses in thoracic aortae of the control and exercise groups were compared. Receptor-binding assays were performed to determine whether there were any upregulations of endothelial receptors after acute exercise. Our results indicated that acute exercise induced the following effects: (1) the dose-response curves of ACh and CLO shifted to the left; (2) the high-affinity M3 binding sites increased in number but not in affinity; (3) the alpha2 binding sites decreased in number but increased in affinity. We conclude that acute exercise enhances receptor-mediated vasodilation responses, at least in part, by regulating either endothelial receptor number or receptor affinity.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylcholine / pharmacology
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Adrenergic alpha-Agonists / analysis
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Adrenergic alpha-Agonists / metabolism
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Adrenergic alpha-Agonists / pharmacology
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Animals
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Clonidine / metabolism
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Clonidine / pharmacology
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Endothelium, Vascular / drug effects
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Endothelium, Vascular / physiology*
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In Vitro Techniques
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Male
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Muscarinic Antagonists / analysis
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Muscarinic Antagonists / metabolism
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Muscarinic Antagonists / pharmacology
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Physical Conditioning, Animal / physiology*
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Piperidines / analysis
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Piperidines / metabolism
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Rats
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Rats, Wistar
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Receptor, Muscarinic M3
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Receptors, Adrenergic, alpha-2 / analysis
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Receptors, Adrenergic, alpha-2 / metabolism*
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Receptors, Muscarinic / analysis
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Receptors, Muscarinic / metabolism*
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Thoracic Arteries / metabolism
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Tritium
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Up-Regulation / physiology
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Vasodilation / drug effects
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Vasodilation / physiology*
Substances
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Adrenergic alpha-Agonists
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Muscarinic Antagonists
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Piperidines
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Receptor, Muscarinic M3
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Receptors, Adrenergic, alpha-2
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Receptors, Muscarinic
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Tritium
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4-diphenylacetoxy-1,1-dimethylpiperidinium
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Clonidine
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Acetylcholine