Biochem/physiol Actions

Compound 21 is a potent designer drug with full agonist activity toward human hM3Dq (EC50 = 1.7 nM by cell-based Ca2+ mobilization assay), a human M3 muscarinic receptor (M3R)-based Gq (M3Dq) DREADD (Designer Receptors Exclusively Activated by Designer Drugs), displaying little activity toward muscarinic acetylcholine receptor M3 (30% M3 activation at 10 µM) and reduced affinity toward H1, 5HT2A, 5HT2C, α1A receptor (fold selectivity = 3.5, 40, 100, 165, respectively). Note: the DREADD hM3Dq exhibits M3 biological activity, but is insensitive to the endogenous ligand acetylcholine (ACh).