Allosteric modulators of ligand binding to muscarinic acetylcholine receptors

Allosteric modulators of muscarinic receptors act at a site apart from the common ligand binding site of the receptor protein. These compounds affect both of the molecular events that determine the level of equilibrium binding, namely ligand association and dissociation. As a consequence, ligand binding can be elevated, reduced or remain unchanged, depending on the receptor subtype, the type of ligand and the type of allosteric modulator. Thus, allosterically acting drugs represent a novel approach for affecting muscarinic receptors, Notably, they may act as subtype-selective enhancers of acetylcholine binding. This might be exploited therapeutically, to improve cognition or to promote antinociception, for example.