Distribution of neuropeptide Y (NPY)-immunoreactive endocrine cells in the gastrointestinal tract of dourado (Salminus brasiliensis)

PEREIRA, R.; VIGLIANO, F.A.; COSTA, L.; ARAÚJO, J.; MOURAD, N.; PAULINO, R.; LOGATO, M.J.; ARRANZ, S.E.; FREITAS, R.; ROSA, P.

Buenos Aires

Simposio; 7th International Symposium on Fish Endocrinology; 2012

Neuropeptide Y is a highly conserved orexigenic peptide that is mainly expressed by hypothalamic neurons but also by endocrine cell of the gastrointestinal tract (GIT). The aim of this study was to describe the distribution of NPY-immunopositive (NPY+) cells in the GIT of the dourado (<span class="keyword">Sspan>alminus brasiliensis) by means of immunohistochemistry. We used 12 juvenile of <span class="keyword">Sspan>. brasiliensis (144.8 g ± 21.7 g). After 24 h of fasting, fish were euthanized and samples from esophagus, stomach (cardial, fundic and pyloric regions), midgut (pyloric caeca, second and third loops) and hindgut were dissected out, fixed in Bouin solution for 12 h and processed for embedding in paraffin wax. Finally, an indirect immunohistochemistry technique using a polyclonal primary antibody against porcine NPY was made, and the number of NPY+ cells mm−2 was calculated in each region. <span class="keyword">Sspan>ignificant differences (p less than 0.05) among regions were assessed by a Kruskal-Wallis test with a Dunn´s post hoc test. Pyloric caeca, the second and third loops of the midgut showed significantly higher values of NPY+ cells mm−2 than the remaining regions of the GIT. The higher density of NPY+ cells at these locations suggest their primary role as a source of peripheral signals for stimulation of food consumption.