||Fig. S2. Embryonic expression of serotonin pathway components.
(A, B) Epidermal expression of monoamine transporter slc18a1 mRNA in stage 14 neurula (A) and stage 35/36 tadpole (B) embryos. Transverse sections (A', B') reveal uniform superficial staining in the epidermis. Note lack of expression in the neural plate at stage 14. (C) tph2 expression was restricted to the hindbrain at stage 30. (C') Transverse histological section. Embryos are shown in lateral views except for panel (A), which shows a dorsal perspective. (D, D') tph1 mRNA expressing SCCs (blue arrowheads) secrete PNA positive vesicles (red arrowheads). (D) Close-up bright field image of a transverse section of a tph1 stained tadpole at stage 36 displaying three SSCs. (D') Fluorescent PNA signals (red) co-localize with tph1 mRNA.