Catecholaminergic cells associated with gill arch blood vessels are neural crest-derived in zebrafish.
(a) Schematic transverse section through ammocoete-stage lamprey gill arch (modified from Ruppert et al., 2003). Red box indicates region shown in b. (b,c) Tyrosine hydroxylase-positive (catecholaminergic) cells are present in the wall of the anterior cardinal vein (arrowheads), closely associated with acetylated tubulin-immunoreactive neurites (arrow). (d) Schematic 25-dpf zebrafish. Dotted line indicates transverse section plane through the gill basket in e-e'''. (e–e''') Tyrosine hydroxylase-positive (catecholaminergic) cells (arrowheads) seen adjacent to melanocyte-covered gill-filament blood vessels (dotted lines), are neural crest-derived (mCherry-positive) in 25-dpf Tg(crestin:creERT2);Tg(-3.5ubi:loxP-GFP-loxP-mCherry) zebrafish. Acv, anterior cardinal vein; Bac, branchial arch cartilage; Bv, blood vessel; Nc, notochord; TH; tyrosine hydroxylase. Scale-bars: 50 μm in b; 25 μm in c,e.