title: Immunohistochemical and ultrastructural evidence of functional organization along the Corydoras paleatus intestine.
abstract: The Neotropical catfish, Corydoras paleatus (Callichthyidae) is a facultative air-breathing teleost that makes use of the caudal portion of the intestine as an accessory air-breathing organ. This portion is highly modified, being well vascularized with capillaries between epithelial cells, which makes it well suited for gas exchange. Instead, the cranial portion is a digestion and absorption site, as it has a typical intestinal epithelium with columnar cells arranged in a single row, villi and less vascularized tunica mucosa. Therefore, the intestine was studied by light and electron microscopy to assess differences between the cranial, middle and caudal portions. To characterize the potential for cell proliferation of this organ, we used anti-proliferating cell nuclear antigen antibody and anti-Na(+) K(+) -ATPase monoclonal antibody to detect the presence of Na(+) /K(+) pump. In C. paleatus it was observed that cell dynamics showed a decreasing gradient of proliferation in cranio-caudal direction. Also, the intestine of this catfish is an important organ in ionoregulation: the basolateral Na(+) /K(+) pump may have an active role, transporting Na(+) out of the cell while helping to maintain the repose potential and to regulate cellular volume.
authors.affiliation: Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias, UNLP. La Plata, Buenos Aires, Argentina.
authors.forename: Silvia E
authors.initials: SE
authors.lastname: Plaul
authors.affiliation: Departamento de Ciencias Morfológicas, Facultad de Ciencias Veterinarias, UNL. Esperanza, Santa Fe, Argentina.
authors.forename: Raquel
authors.initials: R
authors.lastname: Pastor
authors.affiliation: Laboratorio de Histología e Histoquímica, Departamento de Biología, Instituto de Investigaciones Marinas y Costeras (IIMyC), Facultad de Ciencias Exactas y Naturales, CONICET, UNdMP. Mar del Plata, Buenos Aires, Argentina.
authors.forename: Alcira O
authors.initials: AO
authors.lastname: Díaz
authors.affiliation: Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias, UNLP. La Plata, Buenos Aires, Argentina.
authors.forename: Claudio G
authors.initials: CG
authors.lastname: Barbeito
mesh_terms: D000825:Animal Structures / Q000737:chemistry / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D002397:Catfishes / Q000502:physiology*; D005260:Female; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000737:chemistry / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000378:metabolism
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Na+K+-ATPase; Neotropical catfish; PCNA; air-breathing organ