Thus, an unexpectedly complex model for

md neuron-mediated mechanonociception see more is emerging—Pickpocket and DmPiezo detect mechanical loads in parallel, while Painlessp60 and perhaps a dTRPA1 isoform are required for post-transduction signaling, including amplification. The Johnston’s organ (JO) of adult Drosophila antennae is a near-field sound receptor and like other animal ears, the JO relies on mechanical amplification and frequency-selective tuning to optimize sound sensitivity ( Göpfert et al., 2005, Göpfert et al., 2006, Robert and Göpfert, 2002 and Tsujiuchi et al., 2007). Sound is not the only mechanical stimulus detected by the JO, however. This array of hundreds of mechanoreceptor neurons also responds to displacements induced by wind and gravity ( Kamikouchi et al., 2009, Sun et al., 2009 and Yorozu

et al., 2009). Mechanoreceptor cells in the JO project their axons into the antennal nerve and express five TRP channels ( Figure 2B): NOMPC, Nan, Iav, Painless, and Pyrexia. Genetic dissection of hearing and gravitaxis reveals that some channels (Painless, Pyrexia) are needed to sense gravity, others for hearing (NOMPC), and that the TRPV proteins Nan and Iav are expressed broadly and needed for both hearing and gravity sensing. In sound-sensitive chordotonal neurons, the exact function of each TRP channel is matter of continuing investigation. One model (Göpfert et al., 2006) is that NOMPC is essential for detecting BGB324 price sound-induced mechanical stimuli and Nan and Iav work together to both refine mechanical amplification and ensure the proper transmission of stimulus-evoked action potentials in the antennal nerve. In this schema, NOMPC functions like its C. elegans homolog, TRP-4,

and forms the pore of a sensory MeT channel. Techniques for measuring mechanoreceptor currents in the JO are needed to directly test this model, but functional specialization of NOMPC and Nan/Iav is supported Guanylate cyclase 2C by the fact that they occupy distinct compartments in the sensory cilium of JO mechanoreceptors ( Lee et al., 2010 and Liang et al., 2011). Several TRP proteins may be coexpressed in the chordotonal organs of the adult leg that provide information about joint position (Gong et al., 2004, Kim et al., 2003 and Liang et al., 2011). These include NOMPC, Iav, and Waterwitch (Wtrw), which appear to be coexpressed in the campaniform sensilla that detect cuticle deformation in the wings and halteres (Gong et al., 2004, Kim et al., 2003 and Liang et al., 2011). The coexpression of these proteins in other mechanoreceptor neurons suggests that an understanding of how these cells enable mechanosensitivity may depend on cellular context and the entire ensemble of ion channels expressed in each mechanoreceptor. Finally, NOMPC is famous for its expression in the mechanoreceptors that innervate large bristle sensilla on the fly’s body (Walker et al., 2000). NompC mutants lack transient, but retain sustained trans-epithelial mechanoreceptor currents ( Walker et al.