Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that bring about a diversity of fast synaptic actions. Analysis of the Caenorhabditis elegans genome has revealed one of the most-extensive and diverse nAChR gene families known, consisting of at least 27 subunits. Striking variation with possible functional implications has been observed in normally conserved motifs at the acetylcholine-binding site and in the channel-lining region. Some nAChR subunits are particular to neurons whilst others are present in both neurons and muscles. The localization of subunits in non-synaptic regions suggests novel roles for nAChRs. Genetic and heterologous expression studies have identified a subset of nAChR subunits that are important drug targets while the study of mutants has identified genes functionally-linked to nAChRs. Future studies using C. elegans offer the prospect of increasing our understanding of the functional diversity of a complex nAChR gene family as well as addressing the role of nAChRs and associated proteins in human disorders.
Copyright 2003 Wiley Periodicals, Inc.