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. 2019 May 22;5(5):eaaw5141. doi: 10.1126/sciadv.aaw5141

Fig. 3. Physiology of MSNs in taste pegs.

Fig. 3

(A) SEM image of taste pegs. The inner oral surface of two labellar lobes (top) with the boxed region further magnified (bottom). Taste pegs (arrow) are covered by a fold (arrowhead). (B) Peg neurons labeled by NP7506-Gal4. Overlap DIC and GFP images of a labellar slice from a NP7506-Gal4, UAS-SYN21-GFP-P10 fly. The arrow indicates a peg. (C) Peg neurons labeled by NP7506-Gal4 are mechanosensitive. The recorded NP7506 peg neuron fires action potentials to peg deflection but not sucrose and CAF (left); collective data (right; n = 6). Mechanical deflection, 10 μm; sucrose, 100 mM; CAF, 50 mM. (D) Deflection dependence. Spike firing rate increases with peg deflection (top); collective data (bottom; n = 6). The fit is with a Boltzmann function. The deflection amplitudes are indicated. (E) Patch-clamp recordings on peg MSNs. Left: Mechanotransduction currents (deflection, 1 ms and 10 μm; voltage clamp, top); depolarization and action potential firing (current clamp, bottom). Right: A family of superimposed mechanotransduction currents to a 5-ms deflection of 4, 5, 6, 7, 8, and 10 μm (top); the current-displacement relationship (bottom) with X1/2 = 7.0 ± 0.1 μm and Xslope = 1.43 ± 0.01 (n = 6). (F) Dependence of mechanosensitivity of peg neurons on NOMPC. Left: Representative spike firing to sensillar deflection. Right: Collective data. ***P < 0.001. Mechanical deflection, 10 μm. (G) NOMPC is required for mechanotransduction. Left: nompC3 eliminates mechanotransduction currents; nan36a does not affect mechanotransduction currents. Right: Collective data. Mechanical deflection, 10 μm. ***P < 0.001.