Receptors, Muscarinic - genetics, Pulmonary Disease, Chronic Obstructive - diagnosis, Lung - physiopathology, Muscarinic Antagonists - therapeutic use, Chronic Obstructive - genetics, Receptor, Muscarinic M2 - antagonists & inhibitors, Muscarinic M2 - genetics, Chronic Obstructive - physiopathology, Adrenergic, beta-2 - genetics, Chronic Obstructive - drug t...