Fig. 8

Dopaminergic innervation of trigeminal nerve endings and inner ear epithelium. (A) MIP of dorsal part of larval head (Slices 16–40 of 507 μm stack, step size: 1 μm) with the tectum (Tec) and rhombencephalon (RhE) showing potential CA arborizations, which could represent parallel innervation of trigeminal free nerve endings in the skin. Asterisk marks supraorbital neuromast. Arrowheads point to branches of the skin innervation labeled with th:Gal4 driven eGFP-CAAX (TOTO-3: A2 and blue in A1) and faint TH-immunoreactivity (A3, magenta in A1). (B) Sagittal section from XZ-orthoslice at 173 μm of z-stack (dorsal scan, step size: 1 μm, total depth: 462 μm, total width 509 μm) showing the developing inner ear outlined in white with the developing canals of the labyrinth, divided by epithelial pillars (white solid arrows) and relative location of the sensory epithelia with DA innervation (ac, anterior canal; acr, anterior crista; lc, lateral canal; lcr, lateral crista; pc, posterior canal; pcr, posterior crista; sm, saccular macula; um, utricular macula; Whitfield et al., 2002). Gray horizontal lines indicate sections of Z-MIP shown in (C–F). (C). Z-MIP of otic slice stack “C” indicated in (B) (slice 1–125 of 462, step size: 1 μm) with otic capsule (OC). Asterisks mark lateral line neuromasts. On the skin surface potential parallel DA innervation of trigeminal projections (TP) are labeled. Parallel innervation of central lateral line projection in the rhombencephalon is also labeled (CRhP). In the hindbrain most catecholaminergic cell bodies show TH-immunoreactivity but no GFP expression. (D) Z-MIP of otic slice stack “D” indicated in (B) (slice 125–185), showing ac and pc, also posterior to otic capsule the posterior lateral line ganglion (PG) and posterior lateral line nerve (PLLN) with parallel DA innervation (arrowheads). Asterisk marks one of the medial neuromasts on the surface of the OC. (E) Otic slice stack “E” indicated in (B) (slice 185–245) with innervation of sensory epithelia (arrowheads). (F) Otic slice stack “F” as indicated in (B) (slice 245–300) with sensory epithelia of maculae and innervation (arrowheads). In (A–F) asterisks mark neuromasts of the lateral line. Scale bars (A) 100 μm, (B–F) 50 μm. eGFP-CAAX-/SypGFP-expression driven by th:Gal4-VP16: green and panels 2; anti-TH: magenta and panels 3; TOTO-3: blue and panels 4.