Role of Src in hypersensitization to phosphodiesterase inhibitors in beta2-adrenoceptor-desensitized eosinophils

Abstract

When guinea pig eosinophils were incubated with fenoterol, a beta2-agonist, for 120 min, not only desensitization of beta2-adrenoceptors but also hyperresponsiveness to phosphodiesterase (PDE) inhibitors, such as theophylline and rolipram, was observed. The fenoterol-induced beta2-adrenoceptor desensitization was not affected by pretreatment with either genistein, a broad-spectrum tyrosine kinase inhibitor, or PP2, a specific Src family tyrosine kinase inhibitor. On the other hand, both genistein and PP2 abolished the hyperresponsiveness to PDE inhibitors in beta2-adrenoceptor-desensitized eosinophils. These findings suggested that Src family tyrosine kinases play important roles in the hypersensitization of PDE to PDE inhibitors in beta2-adrenoceptor-desensitized eosinophils.