Detection of Paraneuronal Cells in Guppy (Poecilia vivipara) Gill Filament epithelium Determined by Histochemistry and Transmission Electron Microscopy

Abstract

Neotropical teleosts gill show complex organization performing two functions: respiration and osmoregulation. There are several cell types involved in gill epithelial functions, and the target of this study is neuroepithelial cells (NECs), a kind of paraneuronal cell characterized by the ability of synthesizing and storing indolamines in chromaffin granular vesicles. The goal of this study was to verify the presence of NECs in guppy (Poecilia vivipara) gills determined by histochemistry using Lars Grimelius method (LG method) and transmission electron microscopy (TEM) techniques. It was possible to observe NECs in the interlamellar region, either in clusters or isolated on the distal half of the filament, presenting a great amount of dark-brown granules, reactive to LG method. Using sections obtained in microtome, cells with electrodense granules were detected near blood vessels, emitting processes in several directions, evidencing high cellular activity. This fact leads to the hypothesis that these cells act in the regulation of gill functions, probably in the osmoregulation through the synthesis and secretion of chemical messengers. The results confirm the presence of NECs in guppy gills and can be of interest for researchers to utilize this fish species as a potential biological model to refine the study of these type of cells.