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Characterization of adenosine receptors involved in adenosine‐induced bronchoconstriction in allergic rabbits
Author(s) -
ElHashim Ahmed,
D'Agostino Bruno,
Matera Maria Gabriella,
Page Clive
Publication year - 1996
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.1476-5381.1996.tb16031.x
Subject(s) - bronchoconstriction , adenosine , adenosine receptor , medicine , agonist , endocrinology , receptor , adenosine monophosphate , pharmacology , chemistry , asthma
1 Recent work has suggested that adenosine may be involved in asthma via the activation of A 1 receptors. However, the role of the recently cloned A 3 receptor in airways is largely unknown. In the present study, we have investigated the role of the A 3 receptor in adenosine‐induced bronchoconstriction in allergic rabbits. 2 Aerosol challenge of antigen (Ag) immunized rabbits with the adenosine precursor, adenosine 5′‐monophosphate (AMP), resulted in a dose‐dependent fall in dynamic compliance (C dyn ). The maximum fall in C dyn in these rabbits was significantly greater than that in litter matched, sham immunized animals ( P < 0.05). However, there was no significant difference in the maximum increase in airways resistance ( R L ) between Ag and sham immunized rabbits ( P > 0.05). 3 Aerosol challenge of Ag immunized rabbits with cyclopentyl‐adenosine (CPA) (A 1 ‐receptor agonist) elicited a dose‐dependent fall in C dyn in Ag immunized rabbits and the maximum fall in C dyn in these rabbits was significantly greater than that observed in sham immunized rabbits ( P < 0.05). Similarly, CPA induced dose‐dependent increases in R L in Ag immunized rabbits whereas sham immunized rabbits failed to respond to CPA within the same dose range. The maximum increase in R L in Ag immunized rabbits was significantly greater than that of sham immunized rabbits ( P < 0.05). 4 Aerosol challenge of either Ag or sham immunized rabbits with the A 3 agonist aminophenylethy‐ladenosine (APNEA) did not elicit dose‐dependent changes in either R L or C dyn . Moreover, there was no significant difference in the maximum response, measured by either parameter, between the two animal groups ( P > 0.05). 5 These data provide further evidence for a role of the A 1 receptor in the airways, but do not support a role for the A 3 receptor in adenosine‐induced bronchoconstriction in the allergic rabbit.