title: The pineal complex: a morphological and immunohistochemical comparison between a tropical (Paracheirodon axelrodi) and a subtropical (Aphyocharax anisitsi) characid species.
abstract: Cardinal neon Paracheirodon axelrodi and bloodfin tetra Aphyocharax anisitsi are two species of characids with high trade value as ornamental fish in South America. Although both species inhabit middle water layers, cardinal neon exhibits a tropical distribution and bloodfin tetra a subtropical one. In this work, we carried out an anatomical, histological and immunohistochemical study of the pineal complex of P. axelrodi and A. anisitsi. In both species, the pineal complex consisted of three components, the pineal and parapineal organs and the dorsal sac (DS). The pineal organ was composed of a short, thin pineal stalk (PS), vertically disposed with respect to the upper surface of the telencephalon, and a pineal vesicle (PV), located at the distal end of the PS and attached to the skull by connective tissue. The pineal window (PW), a site in the skull where the luminal information accesses the pineal organ, appeared just above the latter structures. In the epidermis of P. axelrodi's PW, club cells were identified, but were not observed in the epidermis of A. anisitsi's one. With respect to the DS, it appeared to be folded on itself, and was bigger and more folded in A. anisitsi than in P. axelrodi. Immunohistochemical assays revealed the presence of cone opsin-like and rod opsin-like photoreceptor cells in the PS and PV. These results provide a first insight into the morphological assembly of the pineal complex of both species, and contribute to a better understanding of the integration and transduction of light stimuli in characids. J. Morphol. 277:1355-1367, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Laboratorio De Neuroendocrinología Y Comportamiento, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina.
authors.forename: Laura
authors.initials: L
authors.lastname: Rincón Camacho
authors.affiliation: Laboratorio De Neuroendocrinología Y Comportamiento, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina.
authors.forename: Leonel
authors.initials: L
authors.lastname: Morandini
authors.affiliation: Laboratorio De Neuroendocrinología Y Comportamiento, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina.
authors.forename: Agustina
authors.initials: A
authors.lastname: Birba
authors.affiliation: Laboratorio De Neuroendocrinología Y Comportamiento, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina.
authors.forename: Luciano
authors.initials: L
authors.lastname: Cavallino
authors.affiliation: División Ictiología, CONICET, Museo Argentino De Ciencias Naturales, Buenos Aires, C1405DJR, Argentina.
authors.forename: Felipe
authors.initials: F
authors.lastname: Alonso
authors.affiliation: Laboratorio De Ecotoxicología Acuática, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina.
authors.forename: Fabiana L
authors.initials: FL
authors.lastname: LoNostro
authors.affiliation: Laboratorio De Neuroendocrinología Y Comportamiento, Departamento de Biodiversidad y Biología Experimental (DBBE), FCEN, UBA E IBBEA, CONICET-UBA, Ciudad Universitaria, Intendente Güirlades 2160, Ciudad Autónoma De Buenos Aires, C1428EHA, Argentina. pandolfi@bg.fcen.uba.ar.
authors.forename: Matias
authors.initials: M
authors.lastname: Pandolfi
mesh_terms: D000818:Animals; D060126:Characidae / Q000033:anatomy & histology*; D029941:Fish Proteins; D010786:Photoreceptor Cells / Q000378:metabolism*; D010870:Pineal Gland / Q000033:anatomy & histology*; D017299:Rod Opsins; D013045:Species Specificity
chemical_list: D029941:Fish Proteins; D017299:Rod Opsins
keywords: characiformes; opsins; pineal complex; pinealocytes