Fig. 7

Development of catecholamine containing elements (blue) in P. dumerilii. Early nectochaete (a-c), mid-nectochaete (d-f), and late nectochaete (g-i); ventral views. a, b and d are combinations of fluorescence (blue) and transmission light image (grey). a: 72 hpf, CA-containing structures in the brain (asterisk), ventral nerve cord (vnc) and larval segments; arrows indicate segmental nerves. b: 72 hpf, the head region showing the brain neuropil (asterisk), two neurons in front of the brain (open arrows), two neurons to the right of it (arrowheads), and four neurons near the right eye (arrows). The pigmented eye looks grey and has two autofluorescent structures (small arrows). c: 72 hpf, high magnification showing CA-containing structures in the paired ventral cord (arrows) and parapodial nerves (arrowheads). d: 3.5 dpf, CA-containing structures in the brain (asterisk), pharynx (ph), ventral nerve cord (vnc), and parapodia (arrows). e: 3.5 dpf, dorsal part of the head showing CA-containing neurites in the brain (asterisk) and pharynx (arrows). f: 3.5 dpf, high magnification of the ventral cord showing two pairs of CA-containing cells in the first (arrows) and second (arrowheads) chaetigerous segments. g: 5 dpf, high magnification of the ventral cord showing five pairs of CA-containing cells (arrows) in the first chaetigerous segment and three pairs (arrowheads) in the second segment (only neurons in the left half of the cord are indicated). h: 5 dpf, high magnification of the dorsal part of the pharynx (ph) showing four CA-containing cells to the left of it (arrows), and one medial cell (arrowhead). i: 5 dpf, high magnification of the ventral part of of the pharynx (ph) showing five CA-containing cells to the right of it (arrows), two controlateral cells (open arrows) and one medial cell (arrowhead). Scale bars = 20 μm