A novel mechanism for coupling of m4 muscarinic acetylcholine receptors to calmodulin-sensitive adenylyl cyclases: crossover from G protein-coupled inhibition to stimulation

Adenylyl cyclases are inhibited during the coupling of muscarinic m4 acetylcholine receptors. Coupling of stimulation of adenylyl cyclase activity is present in the cultured cells and olfactory bulb. The processes of receptor stimulation of adenylyl cyclases are characterized by the compression of m4 receptors and isozymes in HER-293 cells. The compression is performed by calmodulin-sensitive type I and type II adenylyl cyclases.