Morphology of the urogenital papilla and its component ducts in Astyanax altiparanae Garutti & Britski, 2000 (Characiformes: Characidae)

Abstract

The histological description of the urogenital papilla is an important tool to comprehension of the reproductive mechanisms in fish, as well as a pre-requisite to germ cell transplantation in adult fish, besides to be a good biological indicator to environmental changes. Was performed the histological description of the urogenital papilla and its component ducts in the tetra Astyanax altiparanae. The genital and urinay ducts pass separately throughout most part of its extension, joining in a single duct before opening. In males this opening is asymmetric and seems to have double origin, being completely surrounded by striated muscle fibers, while in females it is symmetric and the muscle fibers does not surround it totally. Spermatic duct and oviduct undergo changes throughout their extension, mainly in the morphology of the surrounding epithelium. In the spermatic duct, squamous epithelial cells change to columnar and cuboid with possible secretory activity, close to testes. In the oviduct, anteriorly epithelial cells are also squamous, however, close to ovary there are lamellae composed by a pseudostratified epithelium with columnar and cuboid cells. The urinary duct is highly similar for both sexes presenting globoid cells, which description is known in mammals, however, rare in fish.A descrição histológica da papila urogenital é uma importante ferramenta para a compreensão dos mecanismos reprodutivos em peixes, assim como um pré-requisito para a realização do transplante de células germinativas em peixes adultos, além de um bom indicador biológico de possíveis alterações ambientais. Foi realizada a investigação histológica da papila urogenital e seus ductos constituintes no lambari Astyanax altiparanae. Os ductos genital e urinário ocorrem separadamente ao longo de maior parte de sua extensão, entretanto, unem-se em um ducto simples antes de abrir para o meio externo. Nos machos esta abertura é assimétrica e parece ter dupla origem, sendo completamente envolvida por fibras musculares estriadas, enquanto nas fêmeas ela é simétrica e as fibras musculares não a envolve totalmente. O ducto espermático e oviducto sofrem alterações ao longo de sua extensão, principalmente na morfologia do epitélio que os envolve. No ducto espermático as células epiteliais passam de pavimentosas a colunares e cuboides, com possível atividade secretora, à medida que se aproxima dos testículos. No oviducto, anteriormente as células também são epiteliais pavimentosas, entretanto, próximo aos ovários, formam-se lamelas compostas por um epitélio pseudoestratificado composto por células cuboides e colunares. O ducto urinário é bastante similar em ambos os sexos apresentando células globosas, cuja descrição é conhecida em mamíferos, porém rara em peixes.

Effects of GnRH and the dual regulatory actions of GnIH in the pituitary explants and brain slices of Astyanax altiparanae males

“…For these reasons, the species is of substantial commercial importance (Porto-Foresti et al, 2005). It also serves as a common study model in many topics of research (Adolfi et al, 2015;Camargo et al, 2017;Cassel et al, 2017;Chehade et al, 2015;Costa et al, 2014;Gomes et al, 2013;Jesus et al, 2017;Pereira-Santos et al, 2016;Siqueira-Silva et al, 2015;Yasui et al, 2015). In this context, the aim of this study is to evaluate the effects of chicken GnRH2 (cGnRH2) and zebrafish GnIH-3 (zGnIH-3) on A. altiparanae fshb, lhb, gnrh2 and gnrh3 expression using pituitary explants and brain slices from males.…”

External reproductive structures of male Surfperches (Embiotocidae): Urogenital papilla

“…Our anatomical findings are similar to the histological observations and descriptions of the urogenital papillae in other teleost species. Additionally, the term urogenital papillae has been described as the external opening with both excretory and reproductive structures in several species, for example, the California grunion ( Leuresthes tenuis ; Aryafar et al, 2019), bluehead wrasse (Rasotto & Shapiro, 1998), the gobiid fish ( Trimma okinawae ; Kobayashi et al, 2012), the serranid fish ( Serranus fasciatus ; Hastings & Petersen, 2004), freshwater tetra ( Astyanax altiparanae ; Siqueira‐Silva et al, 2015), and chum salmon ( Oncorhynchus keta ; Uematsu & Hibiya, 1983). We recognize that these histological studies have focused on externally fertilizing species; however, there is little research focused on the papillae of internally fertilizing, marine fishes.…”

Endoscopy and Cannulation as Non-Invasive Tools to Identify Sex and Monitor Reproductive Development in Arapaima gigas

“…In practice, such methods vary according to the species morphology, ranging from external observations of the abdomen and urogenital papilla intumescence (Carosfeld et al, 2003), biochemical analyses of ovarian fluids (Johnson et al, 2014), cannulation and/or massaging out of oocytes and sperm (Rhody et al, 2013;Martins et al, 2017) or through examinations with ultrasound, endoscopy, boroscopy and laparoscopy instruments (Divers et al, 2009;Wildhaber et al, 2005;Kynard and Kieffe, 2002;Albers et al, 2013;Filho et al, 2016). The description of the urogenital anatomy is essential to perform cannulation and assess gonadal development (Siqueira-Silva et al, 2015;Rasotto and Shapiro, 1998;Carlisle et al, 2000). In A. gigas, there is no evident secondary sexual dimorphism in the urogenital papilla between sexes and cannulation so far has been considered impossible (Chu-Koo et al, 2009).…”