Identification and synthesis of low-molecular weight cholecystokinin B receptor (CCKBR) agonists as mediators of long-term synaptic potentiation

Recently, He et al. reported that CCKB receptors located in the neocortex of the brain when bound to their bound natural ligand, CCK peptides, enhance memory, bringing up the possibility that agonists targeting the CCKB receptor may act as therapeutic agents in diseases in which memory loss is marked as observed in dementia and Alzheimer’s. In this report, we describe the synthesis of novel low-molecular weight benzoamine CCKB receptor agonists. The compounds made in this series were determined to be mostly partial agonists, although some antagonists were identified, as well, capable of triggering calcium release in a cell line that overexpresses the CCKB receptor. Compound 35 demonstrated an EC 50 of 0.15 µM in the cell-based assay, but more importantly, several of the compounds, including 35, demonstrated a physiological effect, inducing long-term potentiation in rat brains comparable to the CCK-8 peptide albeit at much higher concentrations. Based on these findings, benzoamines may be the basis for a new series of CCKB receptor agonists in drug-discovery efforts that seek to develop therapeutics to prevent memory loss.