Muscarinic Receptor Subtype Pharmacology and Physiology

Publisher Summary The role of muscarinic receptors is highly complex. The recent pharmacological evidence with novel compounds, together with data from transgenic mice, suggests that all five subtypes (muscarinic M 1 , M 2 , M 3 , M 4 , and M 5 receptors) have a defined function in both peripheral and central nervous systems. Several novel agonists and antagonists have now been identified with authentic subtype specificity in vitro and in vivo , and additional opportunities for selective subtype modulation may arise from the development of selective allosteric regulators. Several clinical development programs are currently underway with selective M 1 agonists, M 1 allosteric regulators, or M 2 antagonists for the treatment of Alzheimer's disease, as well as M 3 antagonists for the treatment of overactive bladder or chronic obstructive pulmonary disease. These compounds may provide novel approaches for a variety of disorders, as well as advancing the current understanding of the metabotropic role of acetylcholine.