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Effect of an inhaled histamine H3‐receptor agonist on airway responses to sodium metabisulphite in asthma.
Author(s) -
O'Connor BJ,
Lecomte JM,
Barnes PJ
Publication year - 1993
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1993.tb05671.x
Subject(s) - asthma , agonist , histamine , medicine , sodium , airway , pharmacology , anesthesia , endocrinology , chemistry , receptor , organic chemistry
Histamine H3‐receptor agonists inhibit excitatory neuro‐transmission in human and guinea‐pig airways. Since neural bronchoconstriction may be important in asthma we have studied the effect of a specific H3‐ receptor agonist R‐alpha‐methylhistamine (alpha MeHA) on bronchoconstriction induced by the inhaled irritant sodium metabisulphite (MBS) in six mild asthmatic subjects in a randomised double‐blind crossover study. Subjects received either alpha MeHA, 10 mg (as a chloride salt) or matched placebo (P) and were then challenged with doubling concentrations of MBS (0.3‐80 mg ml‐1) nebulised from a dosimeter at 5 min intervals with measurement of specific airway conductance (sGaw) and FEV1 at 2 and 4 min respectively after each inhalation. There was no effect of alpha MeHA on baseline airway calibre and the log concentrations of MBS required to lower sGaw by 50% (log PC50) and FEV1 by 20% (log PC20) were not significantly different after alpha MeHA when compared with placebo, suggesting that selective stimulation of airway H3‐receptors does not inhibit MBS‐induced bronchoconstriction.