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The airways response to phenylephrine after blockade of alpha and beta receptors in extrinsic bronchial asthma
Author(s) -
PATEL K. R.,
KERR JAMES W.
Publication year - 1973
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/j.1365-2222.1973.tb01351.x
Subject(s) - phenylephrine , bronchoconstriction , propranolol , blockade , medicine , asthma , alpha (finance) , beta (programming language) , phenoxybenzamine , adrenergic receptor , nadolol , receptor , pharmacology , anesthesia , endocrinology , blood pressure , surgery , construct validity , computer science , patient satisfaction , programming language
Summary Phenylephrine, a powerful alpha receptor stimulant, has been shown to cause a significant fall in the FEV 1 and SGaw in six patients with extrinsic bronchial asthma after prior beta blockade with propranolol. In contrast, propranolol or phenylephrine after prior beta blockade failed to effect a significant change in the FEV 1 and SGaw in five normal subjects. The phenylephrine effect can be completely inhibited by alpha receptor blocking drugs, phenoxybenzamine and thymoxamine. These observations suggest that the bronchomotor tone in asthma is largely controlled by the sympathetic activity and that there are alpha receptors in the human airways which in the presence of beta blockade can be stimulated to give bronchoconstriction.