Fig. 4.

6ʹ-GNTI agonist efficacy requires occupancy of both DOR and KOR in peripheral sensory neurons. Primary cultures of peripheral sensory neurons were transfected with siRNA directed against DOR (gray), KOR (white), or nontargeting siRNA as a control (black). Five days after transfection, inhibition of PGE₂-stimulated cAMP accumulation in response to (A) U50488 (100 nM), (B) DPDPE (100 nM), (C) DAMGO (100 nM), or (D) 6ʹ-GNTI (100 nM) was measured. Data are expressed as the percentage of PGE₂-stimulated cAMP levels and are mean ± S.E.M., n = 6. ***P < 0.001; ****P < 0.0001 versus off-target (control) siRNA, one-way ANOVA with Dunnett’s post test.