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RESPONSE OF HUMAN ISOLATED BRONCHIAL AND LUNG PARENCHYMAL STRIPS TO SRS‐A AND OTHER MEDIATORS OF ASTHMATIC BRONCHOSPASM
Author(s) -
GHELANI A.M.,
HOLROYDE M.C.,
SHEARD P.
Publication year - 1980
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.1476-5381.1980.tb10915.x
Subject(s) - histamine , acetylcholine , parenchyma , contraction (grammar) , bronchospasm , bronchoconstriction , endocrinology , muscarinic acetylcholine receptor , medicine , lung , prostaglandin , antagonist , agonist , chemistry , asthma , pathology , receptor
1 The responses of human isolated bronchial and lung parenchymal strips to cumulative doses of slow reacting substance of anaphylaxis (SRS‐A), histamine, prostaglandin F 2α (PGF 2α ) and acetylcholine have been examined, after storing the tissues overnight in Krebs solution at 4°C. 2 Both tissues contracted to all four agonists. The order of potency (as determined by height of maximal contraction) was: bronchial strip: acetylcholine > histamine = PGF 2α > SRS‐A, and parenchymal strip: PGF 2α > histamine = SRS‐A > acetylcholine. 3 Maximal contractions to SRS‐A of both the human bronchial and parenchymal strips were approx. 30% of the maximal contractions produced by the most potent agonist on each tissue (PGF 2α on the parenchymal strip and acetylcholine on the bronchial strip). SRS‐A, therefore, does not have a powerful direct contractile effect on either parenchymal or bronchial strip of human lung, and is approximately equipotent on both tissues. A part of the broncho‐constrictor activity of SRS‐A in vivo may be mediated via indirect pathways. 4 The selective SRS‐A antagonist, FPL 55712, was approximately equipotent in antagonizing contractions induced by SRS‐A on both human bronchial and parenchymal strips.