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. Author manuscript; available in PMC: 2018 May 2.
Published in final edited form as: Nat Neurosci. 2017 Jun 12;20(8):1085–1095. doi: 10.1038/nn.4580

Figure 4. DP-ilp7 neurons integrate multi-mechanosensory input and facilitate nociceptive behavior.

Figure 4

(a) Inactivation of ilp7 or specifically DP-ilp7 neurons with Kir2.1 but not TnT strongly inhibited nociceptive rolling after both stimuli (n as indicated, p<0.001, chi2 test). (b) CsChrimson mediated acute activation of ilp7 or DP-ilp7 neurons during mechano-nociception. Expression of CsChrimson in ilp7 or DP-ilp7 neurons had no significant effect under low light conditions (CsChrimLow) but strongly facilitated mechano-nociceptive behavior when activated with 625 nm light (CsChrim625nm, 10 mW/mm2, n as indicated, p<0.001, chi2 test). (b’) Legend for scored rolling, bending and non-nociceptive behavior for (a,b,d). (c) Calcium responses of DP-ilp7 neurons expressing GCaMP6m using CsChrimson mediated optogenetic activation of C1da/bd (2-21-Gal4, n=8), C2da (R78A01-Gal4, n=13), C2/C4da (R78A01/ppk-Gal4, n=12), C3da (nompC-Gal4, n=8), C4da (ppk-Gal4, n=8), C2/C3da (C1003.3-Gal4, n=17), C2-4da (C1003.3/ppk-Gal4, n=20), C1-C3da (21-7-Gal4, ppk-Gal80, n=8), C1-C4da (21-7-Gal4, n=9) neurons or mechano-nociceptive stimulation with a 45 mN von Frey filament (n=6). (c’) Maximum responses (ΔFmax/F0) were plotted and compared. Optogenetic activation of C2da neurons was sufficient to elicit calcium responses in DP-ilp7 neurons. DP-ilp7 responses scale with additional activation of C3da and C4da, but not C1da/bd neurons (C2/3da, C2-4, C1-C3da, or C1-C4da), similarly to mechano-nociceptive stimulation (45mn) (5 s activation, 625 nm, 0.2 mW/mm2, *:p<0.05, **:p<0.01, Mann-Whitney test). (d) Mechano-nociceptive behavior of 3rd instar larvae at 96h AEL after the first (I) and second (II) mechanical stimulation with a 45 mN von Frey filament. TnT mediated silencing of C2da, C3da, or C4da strongly inhibits mechano-nociceptive responses (n as indicated, p<0.001, chi2 test). (e) Optogenetic activation of C2da or C3da results in C-bend rolling or contraction behavior, respectively (5 s activation, 625 nm, 0.2 mW/mm2). (f) C2da neuron dependent C-bend rolling is partially inhibited by ilp7 neuron silencing (5 s activation, 625 nm, 0.2 mW/mm2, n as indicated, *:p<0.05, chi2 test).