Abstract
A novel tetrahydroisoquinoline, 1-alpha-naphthylmethyl-6,7-dihydroxy-1,2,3,4- tetrahydroisoquinoline (YS 49) 1) increased heart rate and force in isolated rat atria; 2) relaxed PE- and KCl-contracted rat aorta, and 3) decreased blood pressure and increased heart rate in anesthetized rabbit. These effects were blocked by propranolol, a nonselective beta-antagonist, but not by phentolamine, an alpha-blocker, and/or depletion of catecholamine by reserpine. These results suggest that the mechanism of action of YS 49 is due, at least in part, to beta-adrenergic receptor stimulation.
MeSH terms
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Animals
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Aorta / drug effects
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Blood Pressure / drug effects*
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Female
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Heart Atria / drug effects
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Heart Rate / drug effects*
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In Vitro Techniques
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Isoquinolines / pharmacology*
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Male
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Muscle Relaxation / drug effects
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Muscle, Smooth, Vascular / drug effects*
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Myocardial Contraction / drug effects*
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Phentolamine / pharmacology
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Phenylephrine / pharmacology
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Potassium Chloride / pharmacology
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Propranolol / pharmacology
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Rabbits
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Rats
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Reserpine / pharmacology
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Tetrahydroisoquinolines*
Substances
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Isoquinolines
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Tetrahydroisoquinolines
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YS 49
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Phenylephrine
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Potassium Chloride
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Reserpine
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Propranolol
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Phentolamine