Schimerlik_1989_Annu.Rev.Physiol_51_217

Our knowledge of muscarinic receptor structure, mechanism, and regulation has increased enormously over the past five years. At this time, expression of receptor subtype and coupling via signal transducing elements to specific effector systems seems to be cell or tissue specific events. Determining the specific detailed molecular mechanisms of interaction for the various permutations of receptors and effector proteins and how the effector systems initiate physiological responses are challenging areas for future research.