Fig. 6

a Maximum intensity Z-projection of a confocal stack from a 2 dpf transgenic zebrafish expressing mCyRFP1-referenced GreenT-EC. Scale bar, 200 μm. b Representative orthogonal view of the animal model in the fin fold. Scale bar, 20 μm. c Representative images of skeletal muscle cells (upper panel), vacuolar cells of the notochord and ventral/dorsal muscle (middle panel) and epithelial cells (bottom panel) in the fin fold. Scale bar, 10 µm. d Experimental strategy used for imaging transgenic GreenT-EC zebrafish larvae. After acute or chronic treatment fish are mounted in low melting agarose and the posterior fin fold is imaged. e Confocal images of the fin fold of 4 dpf zebrafish larvae after various treatments. Top: fish larvae under control conditions. Middle: after 10 min treatment with EGTA (3 mM). Bottom: treatment with Calhex231 (10 µM) from 2 dpf to 4 dpf. Scale bar, 20 µm. f Quantification of the EGTA effect (n = 4) on interstitial calcium as GreenT-EC/mCyRFP1 ratio around notochord and dorsal/ventral muscle cells. g Effects of the CaSR inhibitor Calhex231 applied at 5 µM (n = 5) and 10 µM (n = 4) in E2 embryo medium containing 0.03 mM calcium for 48 h. Ratio values were compared with the control group (n = 5). h Effects of Calcitriol 2 µM (n = 6) treatment for 48 h on interstitial calcium around notochord and muscle compared to control animals (n = 5). i Confocal images of the fin fold of 1 dpf control zebrafish larvae (left) or treated with 12.5 µM DafadineA (DafA) (right) during 21 h. Scale bar, 50 μM. j Quantification of the DafA effect on interstitial calcium as GreenT-EC/mCyRFP1 ratio in the notochord (n = 5 for each group). In all experiments, n represents a biological replicate (fish). Two-tailed unpaired t-test were used to calculate the statistical significance between the control and treated groups (f,h,j). For multiple group analyses (g), One-way ANOVA followed by a Tukey multiple comparison test was performed (* p < 0.05, ** p < 0.01, *** p < 0.001 and **** p < 0.0001). Source data are provided in the Source Data file.