THE NKB/DYN-KISS-GNRH SYSTEM IN NON-CANONICAL HYPOTHALAMIC NUCLEI OF SOUTH AMERICAN PLAINS VIZCACHA, LAGOSTOMUS MAXIMUS, (RODENTIA, CAVIOMORPHA)

SCHMIDT AR, INSERRA PIF, CHARIF SE, CORTASA SA, PROIETTO S, CORSO MC; HALPERIN J; ALFREDO DANIEL VITULLO; DORFMAN, VERÓNICA BERTA

Barcelona

Congreso; XIX Congreso de la Sociedad Española de Histología e Ingeniería Tisular; 2017

SOCIEDAD ESPAÑOLA DE HISTOLOGÍA E INGENIERÍA TISULAR

Vizcacha, a rodent that inhabits the Pampean region ofArgentina,shows pre-ovulatory follicle formation during pregnancy with anovulatory process around mid-gestation. We have described the localization ofthe gonadotropin-releasing hormone (GnRH) in neurons of the preoptic (POA) andsupraoptic (SON) areas, and in axonic varicosities of arcuatenucleus (ARC) and median eminence (ME) of female vizcachas. In addition,estrogen receptor alpha (ERα) and progesterone receptor (PR) were localized inGnRH neurons of POA and SON. In other species, GnRH is modulated by factors as Kisspeptin(Kiss), Neurokinin-B (NKB) and Dynorphin-A (Dyn). Kiss conveys feedback ofsteroid hormones on GnRH modulation, while NKB and Dyn colocalize with Kiss neuronsin ARC (called KNDy cells) modulating them. KNDy cells also show ERα and PRexpression and direct inputs to GnRH neurons of POA and ARC. The aim was todescribe KNDy cells in the hypothalamus of the vizcacha and its relation with GnRHand hormone receptors involved in the regulation of the reproduction.We used female vizcachas (n=7) to identify GnRH, Kiss,Kiss receptor GPR54, NKB, DYN, ERα, and PR by immunofluorescence and confocalmicroscopy. Nissl staining was performed to localize hypothalamic nuclei. Kiss receptor colocalized with GnRH neurons in theanteroventricular periventricular nucleus (AVPV/PeVN) and SON, and Kiss localizedin cytoplasms of neurons of AVPV/PeVN and in fibers of SON and ARC. NKB and Dyncolocalized in somas and fibers of AVPV/PeVN and SON, and in a few neurons andfibers of ARC. However, Kiss was not detected in NKB/Dyn neurons. In addition, ERαand PR colocalized in somas of either Kiss or NKB/Dyn cells.This is the first description of the localization of members of theNKB/Dyn?Kiss-GnRH system in the hypothalamus of the vizcacha. The presence of theNKB/Dyn?Kiss system in different neurons, and the lack of Kiss in ARC, suggestan indirect model of NKB/Dyn?Kiss system action on GnRH regulation. Presentresults may indicate that in NKB/Dyn-Kiss-GnRH system, GnRH neurons would beinfluenced by the hormonal environment via ERα and PR, and indirectly by Kissand NKB/Dyn