Allergic sensitization increases the amount of extracellular ATP hydrolyzed by guinea pig leukocytes.

Increased levels of ATP have been found in the bronchoalveolar lavage of patients with asthma, and subjects with this disease, but not healthy subjects, develop bronchospasm after nebulization with ATP. Because the main mechanism for controlling the noxious effects of extracellular ATP is its enzymatic hydrolysis, we hypothesized that allergic sensitization is accompanied by a decreased functioning of such hydrolysis. In the present study, peripheral blood leukocytes from sensitized and non-sensitized guinea pigs were used for determining the extracellular metabolism (as assessed by inorganic phosphate production) of ATP, ADP, AMP, or adenosine, and for detecting possible changes in the expression (qPCR and Western blot) of major ectonucleotidases (NTPDase1, NTPDase3, and NPP1) and purinoceptors (P2X, P2X, P2Y, and P2Y).