Figure 5: GABAergic inhibition of sweet GRNs by MNs.
From: Mechanosensory neurons control sweet sensing in Drosophila
(a) PER in flies with knockdown of GABA-related genes in MNs. Each RNAi line crossed to UAS-dTrpA1;R41E11-GAL4 was subjected to the PER assay. PER was carried out at the indicated temperature. ANOVAs with Tukey post-hoc tests. *P<0.05 (b,c) Food preference of flies with (b) knockdown of GABA-related genes in MNs and (c) knockdown of GABA receptors in sweet GRNs. Flies were given a choice between 0.5 mM sucrose in 0.2% agarose and 1 mM sucrose in 2% agarose. UAS-Dcr2;R41E11-GAL4 (b) and Gr64f-GAL4;UAS-Dcr2 (c) were crossed to each RNAi line. The red dashed line at 0.5 represents no preference. ANOVAs with Tukey post-hoc tests. *P<0.05, **P<0.01. (d,e) Effect of pharmacological GABABR blockade in sweet GRN termini on MN-mediated PER inhibition. (d) Representative traces for fluorescence intensity changes in sweet GRN termini after stimulation with 100 mM sucrose and MN activation in the presence of the GABABR antagonist CGP54626. Gr5a-LexA/+;LexAOp-GCaMP3/+;UAS-dTrpA1/VT2692-GAL4 were used for calcium imaging. Brains were incubated in artificial haemolymph containing 5 μM CGP54626 for 5 min. (e) Normalized inhibition ratio of maximal ΔF/F0. Unpaired Student’s t-tests, *P<0.05, **P<0.01. n is indicated in parentheses. All data are presented as means±s.e.m.
