Fig. 6: mGluR5 mediates myelin sheath growth in response to opto-stimulation of chx10 interneurons.

a, Experimental setup for long-term (16 h) opto-stimulation of individual ChRimsonR-positive and -negative Tg(mbp:memGCaMP7s) fish. Fish were screened for transgenesis, responsiveness to opto-stimulation and placed in individual wells of a 96-well plate and optically stimulated for 16 h before myelin morphology was assessed. b, Representative images, following 16 h of opto-stimulation, of a WT (left) and grm5a^−/−grm5b^−/− mutant (right) expressing Tg(chx10:ChRimsonR–tdTomato;mbp:memGCaMP7s) (ChR⁺) (WT N = 21, grm5a^−/−grm5b^−/− N = 18) (top). Representative images of Tg(mbp:memGCaMP7s), ChRimsonR–tdTomato negative (ChR⁻) WT (left) and grm5a^−/−grm5b^−/− mutants (right) following 16 h of opto-stimulation (WT N = 13, grm5a^−/−grm5b^−/− N = 9) (bottom). Scale bar, 10 µm. c, Avg. myelin sheath length per WT and grm5a^−/−grm5b^−/− ChR⁺ and ChR⁻ animals (one-way ANOVA; P < 0.0001; Tukey’s multiple comparisons; WT ChR⁺ versus WT ChR⁻ P = 0.0032; WT ChR⁺ versus grm5a^−/−grm5b^−/− ChR⁺ P < 0.0001; WT ChR⁺ versus grm5a^−/−grm5b^−/− ChR⁻ P < 0.0001; WT ChR⁻ versus grm5a^−/−grm5b^−/− ChR⁺ P = 0.1636; WT ChR⁻ versus grm5a^−/−grm5b^−/− ChR⁻ P = 0.0488; grm5a^−/−grm5b^−/− ChR⁺ versus grm5a^−/−grm5b^−/− ChR⁻ P = 0.7810) WT ChR⁻ N = 13, 18.02 ± 4.73 WT ChR⁺ N = 21, 22.24 ± 3.16 grm5a^−/−grm5b^−/− ChR⁻ N = 18, 14.24 ± 2.44 grm5a^−/−grm5b^−/− ChR⁺ N = 18, 15.51 ± 2.40. d: Relative frequency distribution of individual sheath lengths, measured post-stimulation (WT ChR⁺ n = 462, 21.67 µm; WT ChR⁻ n = 315, 16.23 µm; grm5a^−/−grm5b^−/− ChR⁺ n = 271, 14.04 µm; grm5a^−/−grm5b^−/− ChR⁻ n = 271, 15.11 µm). Data are shown as mean ± s.d.

Source data