How do indacaterol and glycopyrronium in Ultibro Breezhaler relax airway smooth muscle?

In Ultibro Breezhaler, indacaterol activates beta2-adrenoceptors, acting partly through adenyl cyclase stimulation and increased cyclic AMP to relax bronchial smooth muscle, while glycopyrronium antagonises muscarinic receptors to block acetylcholine-mediated bronchoconstriction, providing additive effects through different pathways.