Evidence that kisspeptin neurons in the AVPV form part of a bisynaptic pathway connecting suprachiasmatic vasopressin neurons with preoptic GnRH cells

Abstract

Event Abstract Back to Event Evidence that kisspeptin neurons in the AVPV form part of a bisynaptic pathway connecting suprachiasmatic vasopressin neurons with preoptic GnRH cells Imre Kalló1, 2*, Barbara Vida1, Levente Deli1, Theodosis Kalamatianos3, Erik Hrabovszky1, Alain Caraty4, Zsolt Liposits1, 2 and Coen W. Clive3 1 Institute of Experimental Medicine, Hungary 2 Pázmány Péter Catholic University, Department of Neuroscience, Faculty of Health,Medicine and Life Sciences, Hungary 3 King’s College London, United Kingdom 4 Univ Tours, INRA, France Gonadotropin releasing hormone (GnRH) secretion is under circadian regulation in rodents, but the mechanisms underlying this are poorly understood. Findings of our previous studies suggest that vasopressin (VP) neurons in the suprachiasmatic nucleus (SCN) convey signals to GnRH neurons via the anteroventral periventricular nucleus (AVPV). The AVPV contains kisspeptin (KP) neurons, which have been implicated in oestrogen’s positive feedback on GnRH release. Our studies have used confocal- and electronmicroscopy to test the hypotheses that direct contacts are made by VP-immunoreactive (IR) processes from the SCN on AVPV KP neurons and by KP-IR processes on GnRH neurons. Unlike the VP neurons in the supraoptic and paraventricular nuclei and in the bed nucleus of the stria terminalis and medial amygdala, those in the SCN are characterised by absence of galanin expression. Triple-label immunohistochemistry for VP, galanin and KP was carried out on hypothalamic sections from ovariectomised mice treated with estradiol benzoate. Confocal microscopy analysis indicated that nearly half of the KP-IR neurons in the AVPV show somatic or dendritic appositions from VP-IR varicosities lacking galanin-immunoreactivity; at the ultra-structural level, type II symmetric synapses were observed. KP-IR terminals were seen on GnRH perikarya and dendrites; these were not labelled for Neurokinin-B, markers of the KP fibers with arcuate nucleus origin. At the ultrastructural level KP-GnRH contacts displayed type I asymmetric synapses. The present results provide confocal and ultra-structural evidence which is consistent with the hypothesis that KP-IR neurons in the AVPV act as intermediaries between VP neurons in the SCN and GnRH neurons. Conference: 12th Meeting of the Hungarian Neuroscience Society, Budapest, Hungary, 22 Jan - 24 Jan, 2009. Presentation Type: Poster Presentation Topic: Homeostatic regulatory mechanisms Citation: Kalló I, Vida B, Deli L, Kalamatianos T, Hrabovszky E, Caraty A, Liposits Z and Clive CW (2009). Evidence that kisspeptin neurons in the AVPV form part of a bisynaptic pathway connecting suprachiasmatic vasopressin neurons with preoptic GnRH cells. Front. Syst. Neurosci. Conference Abstract: 12th Meeting of the Hungarian Neuroscience Society. doi: 10.3389/conf.neuro.01.2009.04.014 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Feb 2009; Published Online: 25 Feb 2009. * Correspondence: Imre Kalló, Institute of Experimental Medicine, Budapest, Hungary, kallo@koki.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Imre Kalló Barbara Vida Levente Deli Theodosis Kalamatianos Erik Hrabovszky Alain Caraty Zsolt Liposits Coen W Clive Google Imre Kalló Barbara Vida Levente Deli Theodosis Kalamatianos Erik Hrabovszky Alain Caraty Zsolt Liposits Coen W Clive Google Scholar Imre Kalló Barbara Vida Levente Deli Theodosis Kalamatianos Erik Hrabovszky Alain Caraty Zsolt Liposits Coen W Clive PubMed Imre Kalló Barbara Vida Levente Deli Theodosis Kalamatianos Erik Hrabovszky Alain Caraty Zsolt Liposits Coen W Clive Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.