NEURONAL NICOTINIC ACETYLCHOLINE-RECEPTOR - FROM GENE TO SMOKING ADDICTION

The nicotinic acetylcholine receptor present in muscle is an allosteric pentameric protein and has been used as a model for the structure and function of the superfamily of ligand gated ion channels. A related family of receptors is localized in the nervous system. These receptors, which are composed of two alpha subunits that are chiefly responsible for the binding of acetylcholine and three non-alpha subunits, mediate neuronal nicotinic neurotransmission. To date, ten genes have been isolated encoding subunits of the neuronal nicotinic receptor expressed in various brain regions. The electrophysiological and pharmacological properties of the neuronal nicotinic receptors are dependent upon the subunit composition of the receptor, and can be modified by innervation as well as by agents such as calcium and cAMP. The expression of the receptor can be altered as a result of diverse neuronal pathologies.