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THE ACTION OF EPHEDRINE ON FOREARM BLOOD VESSELS IN MAN
Author(s) -
Frewin DB,
Whelan RF
Publication year - 1968
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1968.36
Subject(s) - phentolamine , vasoconstriction , vasodilation , ephedrine , medicine , forearm , brachial artery , receptor , adrenergic , sympatholytics , blockade , endocrinology , anesthesia , anatomy , blood pressure
Summary Ephedrine hydrochloride given into the brachial artery has been shown to have two distinct actions on the vessels of the human forearm. The predominant effect is a vasoconstriction which is mediated by release of a constrictor substance from the sympathetic nerve ends acting on α‐adrenergic receptors of the vascular smooth muscle. The second effect is a vasodilatation which is unmasked when the α‐receptors are blocked by phentolamine or when the sympathetic nerves are absent. This effect is due to a direct action of ephedrine on β‐adrenergic receptors. A mild vasoconstriction is seen following blockade of both α‐and β‐receptors and in the β‐blocked sympathectomized limb. The mechanism of this effect is uncertain.