Fig. 7

The innervation of the ciliary band in the mitraria of O. fusiformis. FMRFamide-LIR (yellow) and 5-HT-LIR (purple), aTub-LIR (cyan), DNA (dark blue). Confocal z-projections and volume renderings of aTub-LIR (b, e), FMRFamide-LIR (c) and 5-HT-LIR (e). Ventral is left and apical is up in all images, except (c) and (e) which show a view from ventral. Stages are given in days post fertilization (dpf). a The mitraria exhibits two distinct neurites forming the apical and posterior ciliary ring nerves (acn, pcn) (inset), and three pairs of peripheral nerves (pn1–3) running from apical towards ventral (pn1, pn2) and lateral (pn 3), and innervating the ciliary ring nerves (cn). Furthermore, a single prominent dorsal nerve (dn) runs from apical to the posterior ciliary ring nerve (pcn). The inset shows a higher magnification of the ciliary ring nerves. b The peripheral nerves (pn1–3) and the dorsal nerve (dn) interconnect the apical part of the developing embryo with the ciliary ring nerves (cn). c FMRFamide-LIR in the ciliary ring nerves is restricted to the apical ciliary ring nerve (acn), which also bears numerous FMRFamide-LIR perikarya. The inset shows a confocal z-projection of the same area in same orientation. Only the apical ciliary ring nerve (acn) is visible. This pattern is visible throughout the entire ring nerve also in stages 7 dpf - 21 pdf. d The peripheral nerves (pn1–3) and the dorsal nerve branch off from the circumesophageal connective (cc) at the apical pole of the larva. e 5-HT-LIR in the ring nerve is restricted to the posterior ciliary ring nerve (pcn) and mainly detected close to the esophagus (es). Note the perikarya showing 5-HT-LIR along the anterior ciliary ring nerve (white asterisks). The inset shows a confocal z-projection of the same area in same orientation. Only the posterior ciliary ring nerve (pcn) is visible. The staining shown here appeared to be fragmentary when looking at the entire ring nerve in stages 7 dpf - 21 pdf. acn, apical ciliary ring nerve; at, apical tuft; bn, bell nerve; cc, circumesophageal connective; cn, ciliary ring nerve; dn, dorsal nerve; en, esophageal nerve; es, esophagus; mg, midgut; pcn, posterior ciliary ring nerve; pn1–3, peripheral nerves 1–3. Scale bars = 50 μm. The scale bars only refer to the main images (a, b, d), not to the insets. Note that (c) and (e) are without scale