Fig. 8.

Activation of OR-S6 leads to Ca²⁺ release mediated by activation of the M3-R. (A) Nonanedioic acid–induced coupling of OR-S6 to the promiscuous G protein G α_15olf enables odorants to increase the intracellular Ca²⁺ concentration. (B) Ca²⁺ influx of cells expressing the M3-R when treated with carbachol (100 nM). (C) Treating cells that express both S6 and the M3-R (in the absence of RTP1S) with nonanedioic acid did not affect a Ca²⁺ response triggered by carbachol. (D) In the absence of the M3-R, treating cells expressing OR and RTP1S did not generate a Ca²⁺ response. (E) Increases in intracellular Ca²⁺ in cells expressing OR-S6, RTP1S, and the M3-R in the presence of nonanedioic (100 μM) acid, similar to the response elicited by carbachol (100 nM). (F) Ca²⁺ release is blocked when non-anedioic acid and atropine (1 μM) are simultaneously used to stimulate cells expressing S6, RTP1S, and the M3-R. Data shown here were taken from one experiment; experiments were repeated three times.