title: The secretogranin-II derived peptide secretoneurin modulates electric behavior in the weakly pulse type electric fish, Brachyhypopomus gauderio.
abstract: Secretoneurin (SN) in the preoptic area and pituitary of mammals and fish has a conserved close association with the vasopressin and oxytocin systems, members of a peptide family that are key in the modulation of sexual and social behaviors. Here we show the presence of SN-immunoreactive cells and projections in the brain of the electric fish, Brachyhypopomus gauderio. Secretoneurin colocalized with vasotocin (AVT) and isotocin in cells and fibers of the preoptic area. In the rostral pars distalis of the pituitary, many cells were both SN and prolactin-positive. In the hindbrain, at the level of the command nucleus of the electric behavior (pacemaker nucleus; PN), some of SN-positive fibers colocalized with AVT. We also explored the potential neuromodulatory role of SN on electric behavior, specifically on the rate of the electric organ discharge (EOD) that signals arousal, dominance and subordinate status. Each EOD is triggered by the command discharge of the PN, ultimately responsible for the basal EOD rate. SN modulated diurnal basal EOD rate in freely swimming fish in a context-dependent manner; determined by the initial value of EOD rate. In brainstem slices, SN partially mimicked the in vivo behavioral effects acting on PN firing rate. Taken together, our results suggest that SN may regulate electric behavior, and that its effect on EOD rate may be explained by direct action of SN at the PN level through either neuroendocrine and/or endocrine mechanisms.
authors.affiliation: Depto Histología y Embriología, Facultad de Medicina, Universidad de la República, 11800 Montevideo, Uruguay; Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, IIBCE, 11600 Montevideo, Uruguay.
authors.forename: Paula
authors.initials: P
authors.lastname: Pouso
authors.affiliation: Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, IIBCE, 11600 Montevideo, Uruguay.
authors.forename: Laura
authors.initials: L
authors.lastname: Quintana
authors.affiliation: Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIBINTECH), Provincia de Buenos Aires, Argentina.
authors.forename: Gabriela C
authors.initials: GC
authors.lastname: López
authors.affiliation: Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIBINTECH), Provincia de Buenos Aires, Argentina.
authors.forename: Gustavo M
authors.initials: GM
authors.lastname: Somoza
authors.affiliation: Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, IIBCE, 11600 Montevideo, Uruguay; Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Silva
authors.affiliation: Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. Electronic address: trudeauv@uottawa.ca.
authors.forename: Vance L
authors.initials: VL
authors.lastname: Trudeau
mesh_terms: D000818:Animals; D004555:Electric Fish / Q000235:genetics*; D009479:Neuropeptides / Q000378:metabolism*; D053381:Secretogranin II / Q000378:metabolism*; D014668:Vasotocin / Q000378:metabolism*
chemical_list: D009479:Neuropeptides; D053381:Secretogranin II; C081159:secretoneurin; D014668:Vasotocin
keywords: Electric organ discharge; Neuropeptide; Pacemaker nucleus; Preoptic area; Secretoneurin; Vasotocin