In @entity840 airways, @entity2472 induced by @entity15491 or antigen are thought to be mediated primarily by an action of the agonist or of released mast cell-derived mediators directly on the airway smooth muscle cell. An indirect contractile action mediated by endogenous @entity4756 also has been described for both of these stimuli. The present study evaluated the contribution of endogenous @entity4756 to ovalbumin- and leukotriene D4-induced @entity2472 in the @entity840 bronchus by modulating the concentrations of @entity4756 within the tissues and by using neurokinin receptor antagonists. Acute depletion of @entity4756 with @entity2951 had no effect on responses elicited by either stimulus. Similarly, @entity1022 treatment failed to influence leukotriene D4-induced @entity2472 . Inhibitors of neutral endopeptidase (thiorphan) and angiotensin-converting enzyme ( @entity3593 ) enhanced neurally mediated tachykininergic responses and potentiated leukotriene D4. The latter effect persisted in the presence of @entity1022 or the neurokinin antagonists @entity11714 and @entity21313 and in tissues treated acutely with @entity2951 . The potentiation was absent, however, from bronchi incubated with @entity462 . Ovalbumin-induced @entity2472 were unaltered by inhibition of neutral endopeptidase and angiotensin-converting enzyme. These observations suggest that @entity4756 are not involved in mediation of leukotriene D4- or antigen-induced @entity2472 of the @entity840 bronchus. The ability of protease inhibitors to potentiate leukotriene D4 but not antigen-induced responses is therefore ascribed to inhibition of bioinactivation of @entity4352 D4 to @entity11130 .

Absence of @entity4756 involvement in leukotriene D4 and antigen-induced contraction of XXXX isolated bronchus.

@entity462 :: ('MESH:D003545', 'Chemical') :: ['L-cysteine'] @entity2951 :: ('MESH:D002211', 'Chemical') :: ['capsaicin'] @entity840 :: ('10141', 'Species') :: ['guinea pig'] @entity1022 :: ('MESH:D013779', 'Chemical') :: ['tetrodotoxin'] @entity11714 :: ('MESH:C080755', 'Chemical') :: ['CP99994'] @entity4352 :: ('CHEBI:25029', 'Chemical') :: ['leukotriene'] @entity15491 :: ('MESH:D017998', 'Chemical') :: ['leukotriene D4'] @entity3593 :: ('MESH:D017706', 'Chemical') :: ['lisinopril'] @entity21313 :: ('MESH:C073839', 'Chemical') :: ['SR48968'] @entity11130 :: ('MESH:D017999', 'Chemical') :: ['leukotriene E4'] @entity4756 :: ('MESH:D015320', 'Chemical') :: ['tachykinins'] @entity2472 :: ('MESH:C536214', 'Disease') :: ['contractions']
@entity840 :: (10141,Species) :: ['guinea pig']
