Objective:To investigate the expression of angiotensinⅡreceptor subtypes(AT1R,AT2R) and β2-adrenergic receptor(AR)in the lungs of asthmatic rats,and the influence of valsartan upon their expression. Methods:Fifty Wistar rats were randomly divided into 5 groups,group A(control),group B(asthma),group C1(Valsartan 15 mg/kg),group C2(Valsartan 30 mg/kg),group C3 (Valsartan 50 mg/kg),each containing 10 subjects. The rats were sensitized by 10% ovalbumin peritoneal injection and challenged by 1% ovalbumin aerosol inhalation to establish the asthmatic model. The levels of AT1R,AT2R and β2-AR mRNA and protein in lung tissues were analyzed by reverse transcriptase-polymerase chain reaction(RT-PCR) and Western blot. Results:Comparing with control (group A),the expression levels of AT1R in asthmatic subjects(group B) was significantly increased(P < 0.05). Valsartan decreased the level of AT1R in asthmatic groups(group C1,C2 and C3). A negative correlation between the expression of AT1R and the dose of valsartan was demonstrated(r = -0.96). There was no AT2R expression in control(group A),while in asthmatic subjects(group B) the AT2R expression increased markably. By use of valsartan,the elevated level of AT2R either could not be found(group C1) or markedly decreased(group C2 and C3); Comparing with control(group A),the β2-AR level in asthmatic subjects(group B) was significantly decreased(P < 0.01). By use of valsartan,the positive expression rate of β2-AR increased in group C1,C2 and C3,compared with group B (P < 0.05,respectively). Conclusion:The results suggested that angiotensin II receptors(ATR) should express in rat lung tissues. The ATR might be activated and play a role in asthma attack. The expression and the function of ATR in the asthmatic rats lung may be related with the change of β2-AR. The expression of AT1R and AT2R in the asthmatic rats lung were increased,while β2-AR decreased. Valsartan could inhibit the expression of AT1R and promote the expression of β2-AR.