ABSTRACT
The great majority of acetylcholine effects in the central nervous system are mediated via interaction with muscarinic cholinergic receptors. Muscarinic receptors were initially found to be composed of a single population of binding sites when applying antagonist binding. Muscarinic receptors are mainly localized postsynaptically on soma and dendrites of noncholinergic cells. This chapter reviews the recent data on receptor autoradiography, in situ hybridization histochemistry, and immunocytochemistry of muscarinic receptor subtypes at the light and electron microscopical level by trying to combine the information obtained by different experimental techniques. Application of immunocytochemistry using specific antibodies targeted to various muscarinic receptor subtypes allows a high degree of regional and cellular resolution as compared to receptor autoradiography and can be extended to the ultrastructural level. Receptor autoradiography allows for the anatomic resolution of binding studies but is limited by the specificity of the ligands available.
