PD 168368

PD 168368 (CAS No.: 204066-82-0) is a synthetic small-molecule modulator widely used in biomedical research as a potent, competitive, and selective antagonist of the neuromedin B receptor (NMB-R), a G protein-coupled receptor involved in neuropeptide signaling and cellular proliferation pathways. It exhibits high affinity for NMB-R with binding constants in the low nanomolar range and effectively inhibits neuromedin B-induced intracellular calcium mobilization and inositol phosphate production, thereby enabling mechanistic studies of NMB-mediated signaling. In receptor binding assays, PD 168368 also demonstrates antagonistic activity against the gastrin-releasing peptide receptor, though with substantially lower potency, supporting its relative selectivity within the bombesin receptor family. In addition to its antagonistic profile, PD 168368 functions as a mixed agonist of formyl peptide receptors FPR1, FPR2, and FPR3, displaying potent agonistic activity in the subnanomolar to low nanomolar range in cell-based functional assays, indicating its utility in studying immune-related chemotactic and inflammatory signaling pathways. Beyond receptor pharmacology, PD 168368 has been shown to induce cell cycle arrest and apoptosis in certain cancer cell models and to inhibit angiogenesis and tumor growth in xenograft systems, highlighting its relevance in oncology research. This compound is therefore broadly applied in studies of neuropeptide receptor biology, GPCR signaling, inflammation, and cancer, with experimental concentrations or dosing regimens typically tailored to specific assay systems and research objectives.