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Neuronal circuits in the hypothalamus controlling gonadotrophin‐releasing hormone release: the neuroanatomical projections of kisspeptin neurons
Author(s) -
Yeo ShelHwa
Publication year - 2013
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2013.071944
Subject(s) - kisspeptin , arcuate nucleus , hypothalamus , biology , neuroscience , gonadotropin releasing hormone , retrograde tracing , median eminence , premovement neuronal activity , neuron , medicine , endocrinology , hormone , central nervous system , luteinizing hormone
New findings• What is the topic of this review? Kisspeptin neurons have been implicated as important regulators of mammalian reproduction and fertility. This study aimed to investigate the axonal projections of kisspeptin neurons in adult female mouse brain using classical neuroanatomical tracers. • What advances does it highlight? The tracing results revealed the innervation patterns of kisspeptin neurons in the arcuate nucleus and rostral periventricular area of the third ventricle. These projections highlighted the diversity of brain regions possibly targeted by kisspeptin neurons, suggesting their involvement in the regulation of multiple circuits in addition to the gonadotrophin‐releasing hormone neuronal network. The present study provides a neuroanatomical framework for the further elucidation of the functions of the kisspeptin neuron populations in the arcuate nucleus and rostral periventricular area of the third ventricle.The hypothalamus regulates the key hormonal signalling events essential for reproduction and fertility in mammals. The gonadotrophin‐releasing hormone (GnRH) neurons are the principal neurons of the complex neuronal network that co‐ordinates multiple internal homeostatic and external factors necessary for fertility. Kisspeptin neurons are one of the major regulators of GnRH neuronal activity, but the ways in which kisspeptin neurons, located in the arcuate nucleus (ARN) and rostral periventricular area of the third ventricle (RP3V), control GnRH neurons are poorly understood. This study focused on the use of anterograde and retrograde tracing techniques to establish the neuronal projection patterns of kisspeptin cells in the female mouse brain. Both anterograde and retrograde tracing studies highlight the complexity of the kisspeptin neuronal system and indicate that both ARN and RP3V kisspeptin neurons may participate in a variety of limbic functions. In relationship to the GnRH neuronal network, these investigations demonstrate that rostral ARN kisspeptin neurons may also project to GnRH neuronal cell bodies. However, we found no anatomical evidence to suggest that kisspeptin neurons innervate GnRH nerve terminals in the external layer of the median eminence. These studies provide a neuroanatomical framework for the further elucidation of the functions of the ARN and RP3V kisspeptin neuron populations.