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INVESTIGATION OF THE MECHANISM OF PROPRANOLOL‐INDUCED BRONCHOCONSTRICTION
Author(s) -
MACLAGAN JENNIFER,
NEY URSULA M.
Publication year - 1979
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1979.tb10846.x
Subject(s) - bronchoconstriction , practolol , bronchospasm , propranolol , atenolol , histamine , blockade , anesthesia , airway resistance , pharmacology , medicine , chemistry , airway , asthma , blood pressure , receptor
1 Dose‐related increases in airways resistance (R aw ) and decreases in dynamic lung compliance (C dyn ) were recorded in guinea‐pigs and rats following intravenous injection of propranolol and of the cardioselective β‐adrenoceptor blocking drugs, atenolol and practolol. 2 The bronchoconstriction reached a peak in 2 to 4 min and subsided within 15 min. Repeated injections caused identical responses in the airways. 3 The isomer (+)‐propranolol, which has only weak β‐adrenoceptor blocking activity, produced identical responses when given alone or when given after a dose of the racemate, sufficient to cause measurable β‐adrenoceptor blockade in the lungs. 4 After the initial bronchospasm had subsided, the β‐adrenoceptor blocking drugs and the isomer, (+)‐propranolol, produced potentiation of the bronchoconstrictor effects of 5‐hydroxytryptamine and histamine. 5 Both the bronchospasm and the potentiation occurred in adrenal demedullated rats. 6 The results indicate that the bronchoconstrictor effects of these drugs are unrelated to β‐adrenoceptor blockade in the airway smooth muscle.