Use of Monoclonal Antibodies to Study the Structure and Function of Nicotinic Acetylcholine Receptors on Electric Organ and Muscle and to Determine the Structure of Nicotinic Acetylcholine Receptors on Neurons

Abstract

Abstract : During the past year, we made rapid progress on molecular studies of nicotinic acetylcholine receptors of both the muscle and neuronal types. Human muscle type nicotinic receptors composed of alpha, beta gamma and delta subunits were shown to be produced in large amounts by a cell line. These receptors were characterized electrophysiologically, immunologically, biochemically, and by CDNA sequencing. For the first time, this provides a system which produces relatively large amounts of human muscle acetylcholine receptors for biochemical, molecular genetic, and pharmacological studies. Neuronal nicotinic receptors were immunoaffinity purified from brains of several species and were found to consist of only two kinds of subunits. Multiple receptor subtypes have been found. Receptor proteins have been immunolocalized. Subunit-specific monoclonal antibodies were made which react with human neuronal nicotinic receptors. cDNAs have been identified for both the acetylcholine-binding subunit and the structural subunit of one subtype of neuronal nicotinic acetylcholine receptor. Thus, the complete primary structure of a neuronal nicotinic receptor has been established. This should lead to expression systems in which their functional properties can be conveniently studied and provide further probes for studying their function in situ.