[Regulation of bronchial tone in chronic obstructive pulmonary disease (COPD): role of muscarinic receptors].
Anticholinergic agents have proved to be of particular value in the treatment of COPD, as vagal cholinergic tone appears to be the only reversible component of airway narrowing, opposite to what happens in asthma. Anticholinergics block muscarinic receptors on airway smooth muscle an submucosal gland cells. Three subtypes of muscarinic receptors have been demonstrated in human airways. M1 receptors in parasympathetic ganglia facilitate cholinergic neurotransmission. M3 receptors on airway smooth muscle cells and glands mediate bronchoconstriction and mucus secretion. M2 receptors at cholinergic nerve endings inhibit the release of acetylcholine and therefore act as feedback inhibitory receptors (autoreceptors). Ipratropium bromide is a non-selective muscarinic antagonist and therefore blocks M1, M2 and M3 receptors. Tiotropium is a novel, potent, and long-lasting muscarinic antagonist that has a kinetic selectivity for M1 and M3 receptors because it dissociated very quickly from M2 receptors. Once-daily inhaled tiotropium is a safe and effective bronchodilator useful as a first-line maintenance therapy in COPD.
Abad Santos
F
F
Servicio de Farmacología Clínica, Hospital Universitario de la Princesa, C/Diego de León 62, 28006 Madrid. fabad@hlpr.insalud.es
Novalbos
J
J
Gallego Sandín
S
S
Gálvez Múgica
M A
MA
D001980:Bronchi / Q000187:drug effects / Q000502:physiology*; D001993:Bronchodilator Agents / Q000627:therapeutic use; D006801:Humans; D009241:Ipratropium / Q000627:therapeutic use; D018727:Muscarinic Antagonists / Q000627:therapeutic use; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000378:metabolism*; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000502:physiology*; D012602:Scopolamine Derivatives / Q000627:therapeutic use; D000069447:Tiotropium Bromide
D001993:Bronchodilator Agents; D018727:Muscarinic Antagonists; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D009241:Ipratropium; D000069447:Tiotropium Bromide