– CCG-50014 is the most potent against the regulator of G-protein signaling protein type 4 (RGS4) (IC50 =30 nM) and is >20-fold selective for RGS4 over other RGS proteins. CCG-50014 binds covalently to the RGS, forming an adduct on two cysteine residues located in an allosteric regulatory site. CCG50014, reduces nociceptive responses and enhances opioid-mediated analgesic effects in the mouse formalin test.