ADRB2 and airway hyperresponsiveness: In addition, β2-AR signaling has been proven to be required for the full development of 3 cardinal features of asthma: mucous hypersecretion, airway hyperresponsiveness and the presence of inflammatory cells in the lungs and chronic administration of ICI118551 or nadolol reduced inflammation and mucous metaplasia, that may contribute to airflow obstruction and airway hyperresponsiveness of asthma[7], [9].