Fig. 6
From: Nervous system development in the Pacific oyster, Crassostrea gigas (Mollusca: Bivalvia)
FMRFamide-immunoreactivity (FMRFa-ir) combined with phalloidin staining and serotonin-immunoreactivity (5-HT-ir) in the pediveliger stage (28 dpf) of Crassostrea gigas. Magenta—muscles, phalloidin; blue—nuclei, DAPI. The apical pole is always upward, and the ventral side is on the right. a General view of FMRFa-ir in the 28-dpf pediveliger stage with the cerebro-pleural ganglion (CPG), paired ventral cords (vnc), pedal (PG), and ventral (VG) ganglia located along the vnc. Note the absence of special cerebro-pedal cords separated from the vnc bundles. Solitary posterior neurons (pn) are visible at the most caudal part of each vnc. Peripheral innervations of the velum, gill rudiment (gr), anterior and posterior adductor muscles (an.ad. and post.ad.) and body wall are visible. Inset: High magnification of the PG/VG region exhibiting a chain of FMRFa-ir cells within the VG rudiment. a1 Innervation of anterior adductor muscle (an.ad.) with fibers emanating from the PG. Retractor muscles (ret) are innervated from the VG. a2 A network of thin FMRFa-ir fibers in the foot (f). a3 The FMRFa-ir network along the digestive system (arrowheads, dig.s.) forms a network of the enteric nerve system (ENS). The posterior adductor (post.ad) is innervated by a thick fiber from the VG. inset: High magnification view of the developing gill rudiment (gr) with two parallel, branched fibers emanating from the PG. b General view of 5-HT-ir in the 28-dpf pediveliger stage with CPG, pedal (PG), and ventral (VG) ganglia located along the ventral nerve cords. Solitary posterior neurons (pn) are visible near the most caudal part of each vnc. Peripheral innervations of the velum and anterior and posterior adductor muscles (an.ad. and post.ad.) are visible. c General view of 5-HT in the 35-dpf pediveliger with a well-developed cerebro-pleural ganglion (CPG), and pedal (PG) and ventral (VG) ganglia. Inset: High magnification of the CPG. c1 The anterior adductor and velum are innervated from the CPG and PG. The posterior adductor is innervated from the ventral ganglia. Scale bars =50 μm