title: Urotensin II-immunoreactive neurons in the caudal neurosecretory system of freshwater and seawater fish.
abstract: Antiserum generated against synthetic urotensin II of the goby, Gillichthys mirabilis, was used to localize urotensin II in the caudal neurosecretory system in six species of freshwater teleosts: Cyprinus carpio, Carassius auratus, Oreochromis mossambicus, Oreochromis niloticus, Salmo gairdneri and Plecoglossus altivelis, and six species of seawater teleosts: Acanthogobius flavimanus, Pagrus major, Parapristipoma trilineatum, Trachurus japonicus, Seriola dumerili and Seriola quinqueradiata. In the carp, urotensin II-immunoreactive perikarya were classified into three groups according to their size and shape. Small cells were located in the spinal cord dorsal to the urophysis, medium-sized cells immediately anterior to the urophysis, and large cells anterior to the medium-sized cells. In each group, a small number of nonreactive cells was found. Urotensin II-immunoreactive nerve fibers extended toward the urophysis and terminated around the blood vessels. Other species of teleosts showed a similar immunoreaction to that observed in the carp. The immunoreaction of the urophysis was stronger in seawater fish than freshwater fish. Urotensin II-immunoreactive elements could not be detected in the brains of the carp, goldfish and goby.
mesh_terms: D000818:Animals; D005399:Fishes / Q000033:anatomy & histology*; D007158:Immunologic Techniques; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D014579:Urotensins / Q000378:metabolism*
chemical_list: D010455:Peptides; D014579:Urotensins