Figure 3.

Nitazene compounds are highly selective MOR agonists

(A–C) Gi/o-mediated cAMP inhibition GloSensor (left) and G protein (GoA) dissociation BRET assays (right) showing isotonitazene (A), N-desethyl isotonitazene (B), and fentanyl (C) tested at the MOR (red), KOR (black), and DOR (blue). For each assay, data were normalized to a control compound for each receptor. DAMGO (MOR), DADLE (DOR), and salvinorin-A (KOR); Data represent mean ± SEM and n ≥ 3 for all conditions in each assay.

(D) Transduction coefficients log(E_max/EC₅₀) derived from the cAMP inhibition assays are shown for isotonitazene, metonitazene, N-desethyl isotonitazene, fentanyl, and morphine tested at MOR (red), KOR (black), and DOR (blue). The coefficients were calculated using the control-normalized E_max and EC₅₀ values from the curves in (A–C) and relates to Figure S3.