Figure 4. Neuronal Ca²⁺ spikes are an effector of gliotransmission.

(A-C) Representative GCaMP6s images (A, B) and quantifications (C) of Ca²⁺ spikes of axotomized C4da neurons (labeled by ppk-LexA>LexAop2-myr-GCaMP6s) at 24 hpa, from control larvae bearing repo-Gal4 (panel A) and larvae bearing glial TNT expression (repo>TNT group: repo-Gal4>UAS-TNT, panel B). GCaMP6s color scale: 0–2,500. n=11 and 9.

(D-F) Representative (D, E) and quantifications (F) of Ca²⁺ spikes of axotomized C4da neurons (labeled by ppk-LexA>LexAop2-myr-GCaMP6s) at 24 hpa, from wildtype larvae (Ctrl, panel D) and larvae bearing AdoR deletion mutation (AdoR^−/−, panel E). GCaMP6s color scale: 0–2,500. n=12 and 10.

(G-I) Representative (G, H) and quantifications (I) of Ca²⁺ spikes of axotomized C3da neurons at 24 hpa, from control larvae (repo-Gal80, 19-12-Gal4>UAS-GCaMP6s, panel G) and larvae bearing AdoR overexpression in C3da neurons (AdoR OE group: repo-Gal80, 19-12-Gal4>UAS-AdoR, UAS-GCaMP6s, panel H). GCaMP6s color scale: 50–1,400. n=11 and 12.

(A1-A2), (B1-B2), (D1-D2), (E1-E2), (G1-G2), and (H1-H2) showed individual frames from the time-lapse GCaMP6s traces. Ca²⁺ spikes were quantified from somata indicated by white dashed lines. Scale bar, 20 μm.

Two-tailed unpaired t-test (C, F, and I). **P<0.01, ***P<0.001.

See also Table S1.