[Involvement of angiotensin on adenosine-induced bronchial hyperreactivity].
Adenosine is an endogenously purine nucleoside which plays a significant role in regulation of airways tone and reactivity by multiple and incompletely known mechanisms, including the release of endogenously active peptides from mast cells via activation of the A3 receptors. Our previous results suggested that releasing of enzymes from activated mast cells could activate the intrapulmonary renin angiotensin system (RAS). In this study, we investigated the involvement of angiotensin II (Ang II) in adenosine-induced bronchoconstriction in an experimental model of allergic asthma. On bronchial rings from ovalbumin (OVA) sensitized rats, after in vitro challenge, adenosine induced small contractile effects which became significant after indomethacin pre-treatment. On the other hand adenosine pre-treatment amplified bronchoconstriction induced by the allergen (OVA) challenge and reduced bronchial relaxation of acetylcholine pre-contracted bronchial rings by cumulative doses of terbutaline. All these effects are significantly lower on rats treated with losartan (a blocker of Ang II type 1 specific receptors, AT1) in the last two weeks of sensitization protocol (50 mg/kg/day). Our data confirmed that adenosine induced bronchial hyperreactivity could be partially a result of RAS activation in abnormal conditions as antigen sensitization and challenge.
Cojocaru
Elena
E
Universitatea de Medicină si Farmacie Gr. T. Popa Iaşi, Disciplina de Fiziologie. celena_ro@yahoo.com
Dumitriu
Irina Luciana
IL
Bogdan
Gurzu
G
Costuleanu
Marcel
M
Slătineanu
Simina Mihaela
SM
Petrescu
Gheorghe
G
D000241:Adenosine; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D001980:Bronchi / Q000187:drug effects*; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D016084:Bronchoconstriction / Q000187:drug effects; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects; D010047:Ovalbumin / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D012084:Renin-Angiotensin System / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000378:metabolism* / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D047228:Angiotensin II Type 1 Receptor Blockers; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D000804:Angiotensin II; D010047:Ovalbumin; D000241:Adenosine