β2-Adrenoceptor agonist-mediated inhibition of human airway smooth muscle cell proliferation: Importance of the duration of β2-adrenoceptor stimulation

Abstract

1. Airway hyperresponsiveness in asthma has been ascribed to airway wall thickening as a result of smooth muscle proliferation and hypertrophy. We have previously shown that continuous exposure to the β2-adrenoceptor agonist, salbutamol inhibits mitogen-induced proliferation of airway smooth muscle cells. In the present study, the effects of variable durations and repeated periods of exposure to β2-adrenoceptor agonists on DNA synthesis in human cultured airway smooth muscle have been investigated to model some of the possible pharmacokinetic profiles of these agents following inhalation. DNA synthesis was measured by [3H]-thymidine incorporation. 2. Shorter periods of exposure (up to 2.5 h)..