Abstract
Over the last decade the increasing availability of metabolically- stable non-peptide antagonists targeted at neuropeptide receptors has led directly to a more thorough understanding of the role of neuropeptides in mammalian physiology. By far the majority of these non-peptide neuropeptide receptor antagonists thus far disclosed have been developed from leads identified from broad screening of company compound files or natural product collections, and may thus bear little obvious structural resemblance to the endogenous peptide ligand. This review will focus on an alternative structure-based approach to non-peptide neuropeptide receptor ligand design, referred to as the `peptoid' drug design strategy, in which an appreciation of the structure of the neuropeptide is the key to the success of this approach. The development and current clinical progress of peptoid cholecystokinin and tachykinin receptor ligands that have thus far resulted from this process will be highlighted and used to exemplify the importance of this novel approach.