Increased expression of G.ALPHA.q protein in bronchial smooth muscle of mice with allergic bronchial asthma

In the present study, the change in Gq protein level in bronchial smooth muscle of mice with antigen-induced airway hyperresponsiveness (AHR) was determined. BALB/c mice were actively sensitized and repeatedly challenged with ovalbumin antigen to induce bronchial smooth muscle hyperresponsiveness. The contraction induced by 10 microM AlF4(-) (generated by 10 microM AlCl3 plus 10 mM NaF) of bronchial smooth muscles isolated from the antigen-challenged mice was significantly augmented as compared with that from the control animals. The G alpha q protein level determined by immunoblotting was also significantly increased in bronchial smooth muscles of the antigen-challenged group. Thus, an upregulation of G alpha q protein may be involved in the pathogenesis of bronchial smooth muscle hyperresponsiveness, one of the causes of AHR in asthmatics.