TY - JOUR T1 - Putative roles of leptin on airways reactivity JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p3843 AU - Irina Luciana Dumitriu AU - Elena Cojocaru AU - Bogdan Gurzu AU - Liliana Georgeta Foia AU - Simona Mihaela Slatineanu Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p3843.abstract N2 - There is growing evidence that sustain the associations between the airway hiperreactivity and obesity. Leptin is an adipokine with a not well-established functional role on airways function. The specific airway resistance (sRaw) and isolated bronchial rings reactivity were assessed on obese resistant (OR) and obese prone (OP) rats, fed with hight fat diet. Results were compared with data from Sprague Dawley (SD) rats fed with standard diet. In vitro experiments were performed on main left bronchus rings. Both contraction induced by 10μM acetylcholine (ACh) and terbutaline-induced relaxation were assessed. On OP bronchi, the terbutaline dose-response curve was shifted to the right and the maximal relaxant effect was decreased up to 20%. Leptin pretreatment did not significantly modify terbutaline relaxant effects on OR rats but restored terbutaline effects on OP bronchi. Inhibition of all NO synthases (NOS) with 10μM N(G)-nitro L-arginine methyl ester blocked the leptin effects. Aminoguanidine (inhibitor of inducible NOS) partially prevented the leptin effects. The ACh-induced sRaw variation was not significantly modify by intratracheal administration of leptin on OP, as compared with OR. On the other hand, the exogenous leptin significantly increased the sRaw on OR as compared with SD. These results suggest that leptin could have protective effects on airway hyperresponsiveness by stimulation of NO synthesis due to the activation mainly of constitutive NOS (cNOS), and not only the obesity but also the diet could modify the airways function. ER -