Fig. 5.

Localisation of asterotocin receptor in A. rubens using in situ hybridisation (ISH) and immunohistochemistry (IHC). a Asterotocin receptor transcript-expressing cells (AstRtc) in a radial nerve cord (black arrowheads) and tube feet (white arrowheads). Inset shows the absence of staining with sense probes. b AstR-immunoreactive (AstR-ir) cells (black arrowhead) and processes (arrows and in inset) in a radial nerve cord. Stained fibres in the adjacent tube foot (white arrow). c AstRtc in the circumoral nerve ring. d AstR-ir cells (arrowheads) and fibres (arrow) in the circumoral nerve ring. e AstRtc in a marginal nerve. f AstR-ir cell (arrowhead) and stained process (black arrow) in a marginal nerve. Stained fibres in the adjacent tube foot (white arrow). g AstRtc in a tube foot (black arrowhead). h Ast-ir in a tube foot. i AstRtc in the cardiac stomach. j AstR-ir in the mucosal layer (white arrowhead), basiepithelial nerve plexus (black arrowhead) and visceral muscle layer (black arrow; inset) of the cardiac stomach. k AstRtc in the coelomic epithelium of the body wall. l AstR-ir cell in the coelomic epithelium of the body wall. m AstRtc in the external epithelium of the body wall. n AstR-ir cell in the external epithelium of the body wall. o AstRtc in a papula. p AstR-ir cells in an ambulacral spine. q AstR-ir cells in a pedicellaria. Abbreviations: BNR, basal nerve ring; BNP, basiepithelial nerve plexus; CMLNP, circular muscle layer nerve plexus; Ce, coelom; CBNP, coelomic basiepithelial nerve plexus; CT, collagenous tissue; Di, disc; Ec, ectoneural region; EE, external epithelium; Hy, hyponeural region; Lu, lumen; MN, marginal nerve; ML, mucosal layer; Pa, papula; RHS, radial hemal sinus; TF, tube foot; VML, visceral muscle layer. Scale bars: a, a inset, b, c, g, h, o, p, q = 60 μm; d, e, j = 30 μm; c inset, f, g inset, n = 20 μm; b inset, e inset, f inset, i, i inset, j inset, k, l, m, o = 10 μm