Nonpeptide ligands antagonists

Comparative substructural elements of peptide and nonpeptide ligands i-opioid receptor agonists, angiotensin, and NPY receptor antagonists... 

Numerous ligands have been developied as potential opioid receptor probes in an effort to distinguish between different types of opioid receptors. These include peptide [6,7] and nonpeptide [8] agonists and antagonists. Here we discuss the design and structure-activity relationship studies of 6-selective nonpeptide ligands and the role of conformation of the "address" moiety in conferring selectivity to the Si and 2 subtypes of opioid receptors. 

Sawada Y, Kayakiri H, Abe Y, et al. A new class of nonpeptide bradykinin B2 receptor ligands, incorporating a 4-aminoquinoline framework. Identification of a key pharmacophore to determine species difference and agonist/antagonist profile. 7 Med Chem 2004 47 2667-77. 

The above examples of peptide scaffold- or nonpeptide template-based peptidomimetic agonists or antagonists illustrate various strategies to elaborate bioactive conformation and/or pharmacophore models of peptide ligands at their receptors. In many cases, receptor subtype selectivity has also been achieved by systematic structural modifications of prototypic leads of peptidomimetics. Thus, although the 3D structures of G-protein-coupled receptors (GPCRs) remain as elusive (except for models constructed from homology-based low-... 

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