title: Hyperresponsiveness to adenosine in sensitized Wistar rats over-expressing A1 receptor.
abstract: Airway hyperreactivity is characterized by increased responsiveness to bronchoconstrictor stimuli and it is hallmark of asthma. Adenosine is an ubiquitous signaling nucleoside resulting from ATP catabolism, whose extracellular levels increase following cellular damage or stress. Adenosine plays a role in asthma; asthmatics, but not normal subjects, present bronchoconstriction following inhalation of adenosine or of its precursor, adenosine-5'-monophosphate, most likely via adenosine A(2B) receptor on mast cells. However, the mechanism underling the increased airway smooth muscle sensitivity to adenosine in asthmatics remains to be elucidated. Early experimental studies suggested the involvement of A(1) receptor; this hypothesis has been confirmed by more recent studies on guinea pigs and is corroborated by the finding of an increased adenosine A(1) expression on asthmatic bronchial tissues. Brown Norway rats, the strain usually used to assess asthma models, develop hyperresponsiveness to adenosine 3h following allergen challenge, but not 24h thereafter, without involvement of A(1) receptor. Here, we investigated the role of adenosine A(1) receptor in sensitized Wistar rats showing airway hyperresponsiveness 24h following allergen challenge. We found that on bronchi of sensitized Wistar rats challenged with allergen there is an increased adenosine A(1) receptor expression on smooth muscle that is responsible for hyperresponsiveness to adenosine and ovalbumin.
authors.affiliation: Department of Experimental Pharmacology, Faculty of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Alfieri
authors.forename: Antonio
authors.initials: A
authors.lastname: Parisi
authors.forename: Francesco
authors.initials: F
authors.lastname: Maione
authors.forename: Gianluca
authors.initials: G
authors.lastname: Grassia
authors.forename: Silvana
authors.initials: S
authors.lastname: Morello
authors.forename: Armando
authors.initials: A
authors.lastname: Ialenti
authors.forename: Nicola
authors.initials: N
authors.lastname: Mascolo
authors.forename: Carla
authors.initials: C
authors.lastname: Cicala
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D058916:Adenosine A1 Receptor Antagonists / Q000494:pharmacology; D000485:Allergens / Q000276:immunology; D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D004487:Edema / Q000276:immunology; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology*; D006967:Hypersensitivity / Q000276:immunology* / Q000378:metabolism*; D007114:Immunization; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D013997:Time Factors
chemical_list: D058916:Adenosine A1 Receptor Antagonists; D000485:Allergens; D043682:Receptor, Adenosine A1; D010047:Ovalbumin; D000241:Adenosine