Fig. 3.

Potentiation of OR responses by the M3-R is enhanced by muscarinic receptor agonists but inhibited by muscarinic receptor antagonists. (A to D) Nonanedioic acid dose-response curves for luciferase assays performed in HEK 293T cells expressing (A) the M3-R alone, (B) the M3-R and Rho-tagged OR-S6, (C) Rho-tagged OR-S6 and RTP1S, and (D) the M3-R, Rho-tagged OR-S6, and RTP1S, and the M3-R in the presence of the mucarinic receptor agonist carbachol (100 nM, purple), the muscarinic antagonist atropine (1 μM, green), and carbachol and atropine (black), or in the absence of additional treatment (red). Error bars indicate the SEM; the assays were performed in triplicate.