Figure 2.

ORs responsive to artificial cigarette smoke in vivo. A, In mice exposed to a low concentration of artificial cigarette smoke odor (artCSO), only four receptors respond, and they are all ORs. Delta is the artificial cigarette smoke odor response relative to the clean air control response. B, The distribution of responses, measured as the fold difference (FD) enrichment of receptor mRNAs in samples of active OSNs compared with inactive OSNs, identifies responses specific to artificial cigarette smoke odor versus the clean air control (red). C, Of the responsive ORs, three are closely related to each other and not related to Olfr705, the other responsive OR. D, All four of the ORs responsive to a low concentration of artificial cigarette smoke odor (artCSO) also respond to cigarette smoke (blue squares).