title: Biochemical analysis and immunohistochemical examination of a GnRH-like immunoreactive peptide in the central nervous system of a decapod crustacean, the kuruma prawn (Marsupenaeus japonicus).
abstract: We examined whether a gonadotropin-releasing hormone (GnRH)-like peptide exists in the central nervous system (CNS) of the kuruma prawn, Marsupenaeus japonicus, by reverse-phase high performance liquid chromatography (rpHPLC) combined with time-resolved fluoroimmunoassay (TR-FIA) analysis and by immunohistochemistry. The displacement curve obtained for serially diluted extracts of the kuruma prawn brain paralleled the chicken GnRH-II (cGnRH-II) standard curve obtained by cGnRH-II TR-FIA using the anti-cGnRH-II antibody, which cross-reacts not only with cGnRH-II but also with lamprey GnRH-II (lGnRH-II) and octopus GnRH (octGnRH). Extracts of kuruma prawn brains and eyestalks showed a similar retention time to synthetic lGnRH-II and octGnRH in rpHPLC combined with TR-FIA analysis. Using this antibody, we detected GnRH-like-immunoreactive (ir) cell bodies in the anterior-most part of the supraesophageal ganglion (brain), the protocerebrum. Furthermore, GnRH-like-ir fibers were observed in the protocerebrum and deutocerebrum. In the eyestalk, GnRH-like-ir cell bodies were detected in the medulla interna, and GnRH-like-ir fibers were distributed in the medulla interna, medulla externa, and lamina ganglionalis. In the thoracic ganglion, GnRH-like-ir fibers, but not GnRH-like-ir cell bodies, were detected. No GnRH-like-ir cell bodies or fibers were detected in the abdominal ganglion or ovary. Thus, we have shown the existence and distribution of a GnRH-like peptide in the CNS of the kuruma prawn.
authors.affiliation: School of Marine Bioscíences, Kitasato University, Ofunato, Iwate 022-0101, Japan. amanoma@kitasato-u.ac.jp
authors.forename: Masafumi
authors.initials: M
authors.lastname: Amano
authors.forename: Takuji
authors.initials: T
authors.lastname: Okumura
authors.forename: Kataaki
authors.initials: K
authors.lastname: Okubo
authors.forename: Noriko
authors.initials: N
authors.lastname: Amiya
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Oka
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D003445:Crustacea / Q000033:anatomy & histology* / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007150:Immunohistochemistry
chemical_list: C045152:Gonadorelin-like peptides; D007987:Gonadotropin-Releasing Hormone