title: Gonadotrophin-releasing hormone immunoreactivity in the brain of the tropical freshwater fish, Pygocentrus notatus (Teleostei-Characidae).
abstract: The distribution of GnRH in the brain of the teleost Pygocentrus notatus was demonstrated with the avidin-biotin peroxidase immunocytochemical method using highly specific antibody against synthetic mammalian GnRH. Optimal immunoreaction was obtained using: 1) Bouin's fluid for fixation; 2) repeated incubation with primary antiserum; 3) the use of a detergent in the dilution buffer; 4) the high sensitivity of the avidin-biotin immunoperoxidase method with the cobalt intensification of 3-3' diaminobenzidine tetrahydrochloride; and 5) the use of primary antibody with high specificity. GnRH-immunoreactive (GnRH-ir) in cells and/or axons was observed in all main brain regions. In the forebrain, GnRH-ir was located in a network extending from the caudal part of the olfactory bulb to the telencephalon. GnRH-ir fibres were also observed in the optic tectum, cerebellum and hypothalamus. Two groups of neuronal cell bodies were identified. One group was located in the antero-ventral telencephalon corresponding to the nucleus olfactoretinalis. The second group was found in the rostrodorsal hypothalamus. No GnRH-ir material was detected in the pituitary gland, thus confirming the results of previous studies on brain GnRH-ir distribution obtained by radioimmunoanalysis in this species. These results demonstrate a high degree of similarity between the GnRH systems of P. notatus and other teleost species.
authors.affiliation: Department of Physiology, School of Medicine, University of Venezulea, Caracas.
authors.forename: G
authors.initials: G
authors.lastname: Cáceres-Dittmar
authors.forename: F J
authors.initials: FJ
authors.lastname: Tapia
authors.forename: H Y
authors.initials: HY
authors.lastname: Guerrero
authors.forename: C L
authors.initials: CL
authors.lastname: Paiva
authors.forename: D
authors.initials: D
authors.lastname: Marcano
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000276:immunology; D001923:Brain Chemistry / Q000502:physiology; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D008297:Male; D009412:Nerve Fibers / Q000276:immunology / Q000378:metabolism; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000276:immunology / Q000378:metabolism; D016707:Tissue Fixation
chemical_list: D007987:Gonadotropin-Releasing Hormone