A ligand for the κ-opioid DREADD (EC50s = 11.8 and 160 nM with high or low levels of KORD expression, respectively); pharmacology inactive in unperturbed systems (Ki = 2,950 nM; EC50 = 248 nM); inhibits neuronal firing in neurons expressing KORD with effects dependent upon which brain region is expressing KORD; can be used in combination with CNO because it is inactive at Gq-based DREADDs