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Effect of hydrogen peroxide on guinea‐pig tracheal smooth muscle in vitro : role of cyclo‐oxygenase and airway epithelium
Author(s) -
Rhoden K.J.,
Barnes P.J.
Publication year - 1989
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.1476-5381.1989.tb16898.x
Subject(s) - respiratory epithelium , hydrogen peroxide , guinea pig , isoprenaline , bronchoconstriction , chemistry , epithelium , contraction (grammar) , catalase , histamine , endocrinology , medicine , biochemistry , biology , stimulation , enzyme , asthma , genetics
1 Hydrogen peroxide (H 2 O 2 ) (0.1 μ m ‐3 mM) induced variable contractions of guinea‐pig isolated trachea which were attenuated by catalase (100 u ml −1 ) and mannitol (15 mM) suggesting that contractions were induced by H 2 O 2 and/or the hydroxyl anion. 2 Epithelial removal potentiated contractile responses of tracheal preparations to H 2 O 2 with a leftward shift of the concentration‐response curve and an increase in the maximal response. 3 Indomethacin (3 μ m ) inhibited contractions to H 2 O 2 of intact preparations and preparations without epithelium suggesting that contractions may be mediated by cyclo‐oxygenase products. Intact preparations (but not preparations without epithelium) contracted in response to high concentrations (>0.1 mM) of H 2 O 2 in the presence of indomethacin suggesting that other excitatory factor(s) released by the epithelium may induce contraction. 4 Preincubation of intact tracheal preparations with H 2 O 2 (1 mM) for 1 h had no effect on responses to histamine or isoprenaline. 5 These results suggest that hydrogen peroxide generated during the inflammatory process may play a role in bronchoconstriction.