RHOA and airway hyperresponsiveness: Ca2+ sensitization related to the RhoA/Rho-kinase pathway contributes not only to muscarinic contraction [125] but also to augmented response to muscarinic agonists [60,62,63], indicating that this Ca2+ sensitization is probably associated with symptoms (dyspnea, wheezing) and the pathophysiology (airflow limitation, airway hyperresponsiveness) in COPD.