Immunohistochemical cell types in the terminal nerve ganglion of the cloudy dogfish, Scyliorhinus torazame, with special regard to neuropeptide Y/FMRFamide-immunoreactive cells.

Previous studies showed immunoreactivities for neuropeptide Y (NPY), molluscan cardioexcitatory tetrapeptide (FMRFamide), and gonadotropin-releasing hormone (GnRH) in the terminal nerve of elasmobranchs. The present immunohistochemical study demonstrated two types of cells, i.e. GnRH- and NPY/FMRFamide-positive cells, in the terminal nerve ganglion of the elasmobranch Scyliorhinus torazame. The second cell type (non-GnRH element) contained a substance with a common structure or epitope recognized by anti-NPY and anti-FMRFamide antibodies. The NPY/FMRFamide-like immunoreactivity was associated with granules 70-130 nm in diameter, found in the cell bodies, axons, and axon endings.