Fig. 6

Putative pre-synaptic structures in dopaminergic fibers innervating lateral line neuromasts. (A) Lateral view (MIP) of L2 NM immunofluorescence labeled in transgenic th:Gal4, UAS:SypGFP 6 dpf larva to highlight synaptic structures. (A1) Merged image of channels shown in (A2–A4). Total depth of 47 μm. SypGFP green and in (A2), anti-TH magenta and in (A3), TOTO-3 blue and in (A4). Arrowheads point to putative synaptic structures. (B) Dorsal view (MIP) of SO1 and SO2 NM in the anterior lateral line, immunofluorescence labeled in transgenic th:Gal4, UAS:SypGFP 6 dpf larva. (B1) Merged image of channels shown in (B2–B4) Total depth of 59 μm. SypGFP green and in (B2), anti-TH magenta and in (B3), TOTO-3 blue and in (B4). Arrowheads point to putative synaptic structures. Asterisks: Putative axonal transport vesicles containing synaptophysin. (C) Lateral view (MIP) of L3 NM, immunofluorescence labeled in transgenic th:Gal4, UAS:SypGFP, UAS:EGFP-CAAX larva, with retrograde fill from lateral line nerve with rhodamine dextran (RH) dye to trace the afferent neurons. (C1) Merged image of channels shown in (C2–C4). Afferent neurons labeled with rhodamine dextran shown in magenta and in (C2), SypGFP/EGFP-CAAX green and in (C3), anti-TH blue and in (C4), total depth of: 34 μm. Arrow heads point to putative synapses between the afferent neuron (magenta) and the efferent DA projection (blue, anti-TH immunoreactivity). Asterisk indicates axon of DA projection passing by the L3 neuromast. (D) Lateral view of L4 NM (MIP, same fish as in C). (D1) Merged image of channels shown in (D2–D4), total depth of 37 μm. Arrowheads point to putative synapses between the afferent neurons (magenta) and the efferent DA projection labeled with GFP (green, and D3) and anti-TH (blue, and D4). The projection labeled by the expressed GFP enters NM L4. Step size for (A–D) 1 μm. Scale bars (A,B) 20 μm, (C,D) 10 μm.