4-DAMP

4-DAMP is a M₃ cholinergic receptor antagonist, with a K_d value of 0.5 nM for the M₃ cholinergic receptor expressed in the gastric smooth muscle cell. M₃ cholinergic receptors are the predominant subtype of muscarinic acetylcholine receptors, which mediates the parasympathetic control of smooth muscle contraction and glandular secretion, muscarinic acetylcholine receptor agonist-induced increases in food intake and body weight, as well as the sympathetic cholinergic control of sweating. 4-DAMP is thought to be selective for M₃ receptors in peripheral tissues, but only exhibits limited selectivity for muscarinic receptors in the central nervous system.

References:

1. Murthy KS, Makhlouf GM. Differential coupling of muscarinic m2 and m3 receptors to adenylyl cyclases V/VI in smooth muscle. Concurrent M2-mediated inhibition via Galphai3 and m3-mediated stimulation via Gbetagammaq. Journal of Biological Chemistry, 1997, 272(34): 21317-21324.

2. Joan HB, Nora L. Chapter 15 - Acetylcholine and Muscarinic Receptors. Primer on the Autonomic Nervous System (Third Edition), 2012, 75-78.

3. Collins D, Smith DA, Messer WS Jr. Regional binding of 4-diphenylacetoxy-N-methylpiperidine methobromide (4-DAMP) to muscarinic receptors in rat brain and comparative analysis of minimum energy conformations. Neurochemistry International, 1993, 22(3): 237-247.

4. Teixeira-Neto FJ, McDonell WN, Black WD, et al. Effects of muscarinic receptor antagonists on acetylcholine-induced contractions of jejunal smooth muscle in horses. Journal of Veterinary Pharmacology and Therapeutics, 2012, 35(4): 313-318.