[Role of bronchodilators in therapy for COPD-mechanisms of LABA and LAMA on airway smooth muscle].

Long-acting β2-adrenergic receptor agonists (LABAs) and anticholinergics (LAMAs) are widely used clinically as therpy for COPD. Clinical reports have demonstrated that LABAs (salmeterol, formoterol, indacaterol, olodaterol, vilanterol) and LAMAs (tiotropium, glycopyrronium, umeclidinium, aclidinium) are useful to improving symptoms and lung function, and to reducing exacerbation and hospitarization. LABAs expect salmeterol are strong partial agonists, and LAMAs are non-specific antagonists. Ca2+ dynamics and Ca2+ sensitization contribute to relaxation of airway smooth muscle in these bronchodilators. LABAs act on orthosteric and allosteric sites on the β2-adrenergic receptors. In contrast, LAMAs act not only on orthosteric site on the muscarinic receptors, but also allosteric site on the β2-adrenergic receptors, leading to enhancing β2-adrenergic action. Allosteric GPCR modulation is involved in the synergistic effects between LABAs and LAMAs.