Ganglion cells and displaced amacrine cells density in the retina of the collared peccary (Pecari tajacu)

Abstract

In the present study, we investigated the topographical distribution of ganglion cells and displaced amacrine cells in the retina of the collared peccary (Pecari tajacu), a diurnal neotropical mammal of the suborder Suina (Order Artiodactyla) widely distributed across central and mainly South America. Retinas were prepared and processed following the Nissl staining method. The number and distribution of retinal ganglion cells and displaced amacrine cells were determined in six flat-mounted retinas from three animals. The average density of ganglion cells was 351.822 ± 31.434 GC/mm 2. The peccary shows a well-developed visual streak. The average peak density was 6,767 GC/mm 2 and located within the visual range and displaced temporally as an area temporalis. Displaced amacrine cells have an average density of 300 DAC/mm 2 , but the density was not homogeneous along the retina, closer to the center of the retina the number of cells decreases and when approaching the periphery the density increases, in addition, amacrine cells do not form retinal specialization like ganglion cells. Outside the area temporalis, amacrine cells reach up to 80% in the ganglion cell layer. However, in the region of the area temporalis, the proportion of amacrine cells drops to 32%. Thus, three retinal specializations were found in peccary's retina by ganglion cells: visual streak, area temporalis and dorsotemporal extension. The topography of the ganglion cells layer in the retina of the peccary resembles other species of Order Artiodactyla already described and is directly related to its evolutionary history and ecology of the species.

Enhanced glaucomatous damage accompanied by glial response in a new multifactorial mouse model

“…Retinal cross-sections (n=5/group) were stained with Nissl to evaluate the number of neurons in the ganglion cell layer (GCL) ( 57 , 63 ). Briefly, after de- and rehydration in 70 to 100% ethanol, cross-sections were stained with the 1% cresyl violet (Merck Millipore).…”

Estudos comparativos da morfologia da retina de Bothrops jararaca e Crotalus durissus (Serpentes, Viperidae)

“…A faixa visual (Figura 9) é uma especialização caracterizada por uma área alongada de maior densidade de células que pode se estender ao longo do eixo vertical ou mais comumente, ao longo do eixo horizontal da retina (Brown, 1969;Fernández-Juricic et al, 2011;Hughes, 1977). Em geral, esta especialização pode ser observada em animais que ocupam ambientes de campo aberto, sem obstrução do campo visual pela vegetação, de forma que a faixa visual fica alinhada com a linha do horizonte, como observado no porco-do-mato (Pecari tajacu) (Costa et al, 2020) (Figura 9), ou em animais que habitam intermediações entre terra e água, como a tartaruga-de-orelha-vermelha (Trachemys scripta elegans) (Grötzner et al, 2019). A faixa horizontal permite, portanto, uma visão panorâmica do ambiente sem a necessidade da movimentação da cabeça (Lisney et al, 2013).…”