Synthesis, Pharmacological Characterization, and Structure-Activity Relationships of Noncanonical Selective Agonists for ?7 nAChRs.

ABSTRACT: A lack of selectivity of classical agonists for the nicotinic acetylcholine receptors (nAChR) has prompted us to identify and develop a distinct scaffold of ?7 nAChR-selective ligands. Noncanonical 2,4,6-substituted pyrimidine analogues were framed around compound 40 for a structure-activity relationship study. The new lead compounds activate selectively the ?7 nAChRs with EC₅₀'s between 30 and 140 nM in a PNU-120596-dependent, cell-based calcium influx assay. After characterizing the expanded lead landscape, we ranked the compounds for rapid activation using Xenopus oocytes expressing human ?7 nAChR with a two-electrode voltage clamp. This approach enabled us to define the molecular determinants governing rapid activation, agonist potency, and desensitization of ?7 nAChRs after exposure to pyrimidine analogues, thereby distinguishing this subclass of noncanonical agonists from previously defined types of agonists (agonists, partial agonists, silent agonists, and ago-PAMs). By NMR, we analyzed pK_a values for ionization of lead candidates, demonstrating distinctive modes of interaction for this landscape of ligands.

SUBMITTER: Camacho-Hernandez GA 

PROVIDER: S-EPMC7768633 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature