A partial involvement of histamine in ultrasonically nebulized distilled water‐induced bronchoconstriction in guinea‐pigs

Abstract

1 Inhalation of ultrasonically nebulized distilled water (UNDW) can induce bronchoconstriction only in asthmatics, but mechanisms of the response are not well known. We recently reported a guinea-pig model of UNDW-induced bronchoconstriction (UNDW-IB) in which UNDW induces bronchoconstriction when UNDW is inhaled 20 min after a challenge with aerosolized ovalbumin (OA) in passively sensitized, anaesthetized and arti®cially ventilated guinea-pigs. 2 To elucidate the role of histamine in the UNDW-IB, we examined the eects of antihistamines, diphenhydramine hydrochloride (DH) and chlorpheniramine maleate (CP), and measured histamine content in bronchoalveolar lavage¯uid (BALF) in the animal model. 3 DH in doses of 0.1, 1.0 and 10 mg kg 71 and CP in doses of 0.01, 0.1 and 1.0 mg kg 71 administered intravenously 15 min after the OA challenge partially reduced the UNDW-IB at 1 and 2 min after the UNDW inhalation in a dose-dependent manner. Histamine content in BALF recovered 10 min after the UNDW inhalation following the OA provocation was signi®cantly increased compared with that after saline inhalation and before the UNDW inhalation following the OA challenge. 4 Intravenous atropine in a dose of 0.5 mg kg 71 or inhaled disodium cromoglycate in concentrations of 1 and 10 mg ml 71 did not alter the UNDW-IB. 5 These results suggest that histamine is involved in part in the UNDW-IB in our animal model.

Difference in Bronchoprotective Effects of Bronchodilators on Postallergic Propranolol-Induced Bronchoconstriction

“…This result suggests that aminophylline m ay keep it s bronchodilator activity even in b -blockade state. A tropine giv en 15 m in utes after antigen challenge did not reduce the antigen-induced increase in the P ao or prevent the distilled waterinduced bronchoconstriction [ 21] or PI B, w hereas it did reduce antigeninduced bronchoconstriction w hen administered before the antigen challenge. I t is speculated that cholinergic innervation m ay be decreased by antigeninduced bronchoconstriction, but it is possible that anesthesia becom es deeper w ith tim e. W e do not know the exact reason for the ab sence of eÚ ect of atropine on PI B in our guinea pigs model.…”

Ultrasonically nebulized distilled water prevents exogenous histamine hyperreactivity in Toxocara canis-infected mice

“…Histamine involvement was observed in a guinea pig model of UNDW-induced bronchoconstriction [7], suggesting a role for mast cell degranulation in this phenomenon. Protein concentration in the BALF increased significantly in T. canis-infected mice at 14 and 28 days p.i.…”

“…At 24 days p.i., UNDW inhalation increased histamine release into BALF from the T. canis-infected group above the levels found in the infected group that had not received inhalation. In fact, it has also been suggested that inhalation of UNDW could lead to mast cell lysis and histamine release [5,7] and consequently induce protein extravasation. In vitro studies have demonstrated that mast cells can release histamine when exposed to hypotonic solutions [6,29].…”

“…Nonisotonic solutions can induce mediators release from some inflammatory cells such as basophils and mast cells in vitro [6]. Moreover, a guineapig model of UNDW-induced bronchoconstriction was developed and the partial involvement of histamine in UNDW-induced bronchoconstriction was demonstrated in this model [4,7].…”

Influence of alpha‐adrenoceptor blockade on antigen‐ and propranolol‐induced bronchoconstriction in guinea‐pigs in vivo

“…On the other hand, some researchers reported that alpha‐adrenergic agonists enhance mediator release ( Kaliner, Orange & Austen, 1972) and others studied the correlation between alpha‐adrenoceptor and mucus secretion ( Ueki, German & Nadel, 1980). Therefore, we hypothesized that differences of mediator mechanisms in pathogenesis of bronchial asthma may be one of the reasons for the conflicting results ( Songür et al , 1994 ; Songür et al , 1995 ; Fujimura et al , 1996a,b,c, 1998a,b ; Yoshiwara et al , 1996 ).…”