Nitric Oxide’s First Kiss : A Story about the Relationship of Nnos and Kisspeptin in the Hypothalamus

Presentation Number: LB SAT 56
Date of Presentation: April 1st, 2017

Konstantina Chachlaki*1, Samuel Andrew Malone2, Erik Hrabovszky3, Heike Munzberg4, Paolo Giacobini1, Fabrice Ango5 and Vincent Prevot6
1INSERM U1172, University of Lille 2, France, Lille, France, 2university lille 2, LILLE, France, 34 Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Budapest, Hungary, 4Pennington Biomedical Research Center, Baton Rouge, 5Inserm, U1191, University of Montpellier, 6INSERM UMRS1172 Lille2 University, Lille, France

Abstract

The nitric oxide (NO) and the signaling pathways that it regulates are key actors in many cell functions of the brain, especially in the neuroendocrine control of reproduction. Distinct populations of NOS neurons, mainly the ones located in the anteroventral periventricular nucleus (AVPV), the organum vasculosum laminae terminalis (OVLT) and the median preoptic nucleus (MEPO), in the preoptic area (POA), were found to be closely apposed to kisspeptin fibers. These nNOS neuronal populations are known to express the kisspeptin receptor (GPR54), suggesting that they can probably directly receive kisspeptinergic signals (1). The notion that nNOS neurons express functional Gpr54 kisspeptin receptors is further supported by experiments showing that exogenous kisspeptin treatment promotes Gpr54-dependent Ser-1412 phosphorylation of nNOS in diestrus mice, while NMDA can elicit the LH release in Gpr54- and Kiss1-null mice by acting, at least in part, on nNOS neurons (2). Kisspeptin neuronal cell bodies residing in the AVPV region are believed to be part of the glutamatergic family of neurons, participating in the positive feedback action of estrogen in the hypothalamus. Recently we demonstrated that nNOS expressing cells residing in the preoptic hypothalamic area, including the ones found in the region of AVPV, are not only sharing a glutamatergic identity, but also express the estrogen receptor alpha, opening the exciting possibility that these cells could work along with the kisspeptin neurons to promote the estrogenic positive feedback action. Shedding light into the interaction of the kisspeptin and nNOS populations of the preoptic area will certainly help us understand better their eventual contribution to the regulation of the hypothalamic-pituitary-gonadal axis.

 

Nothing to Disclose: KC, SAM, EH, HM, PG, FA, VP