Fig. 4

Occurrence of myoinhibitory peptide (MIP) in the median organ of Sabellariidae. Confocal maximum projections of α-tub-LIR (white), MIP-LIR (red) and DAPI (blue) staining. Anterior is up in all images. All views are from dorsal, except of (c) and (d) which are apical views. The shape of the median organ is indicated by dashed lines and prominent immunoreactive perikarya are marked with arrowheads. Age of the larvae is given in days post fertilization (dpf) and the species identity as well as the colour code for the shown staining is specified in the respective figure. a Distinct MIP-LIR is exhibited close to the brain (br), at the base of the median organ and along the palps (pl). b The median organ tip exhibits immunoreactive somata as well. c, d An anti-MIP staining without counterstaining illustrates the position of the prominent somata with MIP-LIR at the base of the median organ. br, brain; nm, neurite bundle innervating the median organ; pl, palps; pt., prototroch. Scale bars = 80 μm