Abstract
Histamine and the muscarinic agonists, methacholine, oxotremorine, and McN-A-343, were used to contract guinea-pig tracheal smooth muscle preparations. Cumulative dose-relaxation curves with isoprenaline were performed subsequently. In addition, the concentration-dependent induction of phosphoinositide metabolism by the contractile agonists was measured in bovine tracheal smooth muscle. All agonists were found to induce a decrease of the apparent affinity of isoprenaline and a loss of relaxation, depending on the concentration and type of contractile agonist used. The differential effects of the contractile agonists, especially at higher and supramaximal concentrations, on these beta-adrenergic parameters could be explained by differences in phosphoinositide metabolism.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / pharmacology
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Adrenergic beta-Agonists / pharmacology*
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Animals
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Cattle
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Female
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Guinea Pigs
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Histamine / pharmacology
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In Vitro Techniques
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Isoproterenol / pharmacology
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Male
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Methacholine Compounds / pharmacology
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Muscle Contraction / drug effects
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Muscle Relaxation / drug effects
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Muscle, Smooth / drug effects*
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Muscle, Smooth / metabolism
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Oxotremorine / pharmacology
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Phosphatidylinositols / metabolism*
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Respiratory System / drug effects
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Trachea / drug effects
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Trachea / metabolism
Substances
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Adrenergic beta-Agonists
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Methacholine Compounds
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Phosphatidylinositols
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(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride
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Oxotremorine
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Histamine
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Isoproterenol