KNDy neurons are named for their co-expression of three neuropeptides
kisspeptin
neurokinin B (NKB) and dynorphin A (DynA). These cells
located in the hypothalamic arcuate nucleus (ARC)
are associated with generation of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) pulses to control follicular growth and steroidogenesis. However
subcellular sorting mechanisms for secretory vesicles containing these neuropeptides have not been elucidated. In this study
we analyzed the localization pattern of kisspeptin
NKB and DynA in the ARC of the ovariectomized rat immediately treated with estrogen using immunoelectron microscopy. First
we identified neuropeptides by dual-labeled fluorescence immunohistochemistry
with results indicating all three neuropeptides co-express within individual ARC cells in female rats. Next
we investigated the subcellular localization pattern of kisspeptin
NKB
and/or DynA using post-embedding double immunoelectron microscopy
indicating that each type of neuropeptide is contained within separate and individual neurosecretory vesicles. This suggests sorting and packaging of kisspeptin
NKB and DynA is differentially regulated within KNDy neurons. Our findings facilitate understanding of regulatory mechanisms underlying kisspeptin secretion in KNDy neurons
and generation of GnRH/LH pulses induced by kisspeptin in the ARC. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
