title: Surge-Like Luteinising Hormone Secretion Induced by Retrochiasmatic Area NK3R Activation is Mediated Primarily by Arcuate Kisspeptin Neurones in the Ewe.
abstract: The neuropeptides neurokinin B (NKB) and kisspeptin are potent stimulators of gonadotrophin-releasing hormone (GnRH)/luteinsing hormone (LH) secretion and are essential for human fertility. We have recently demonstrated that selective activation of NKB receptors (NK3R) within the retrochiasmatic area (RCh) and the preoptic area (POA) triggers surge-like LH secretion in ovary-intact ewes, whereas blockade of RCh NK3R suppresses oestradiol-induced LH surges in ovariectomised ewes. Although these data suggest that NKB signalling within these regions of the hypothalamus mediates the positive-feedback effects of oestradiol on LH secretion, the pathway through which it stimulates GnRH/LH secretion remains unclear. We proposed that the action of NKB on RCh neurones drives the LH surge by stimulating kisspeptin-induced GnRH secretion. To test this hypothesis, we quantified the activation of the preoptic/hypothalamic populations of kisspeptin neurones in response to POA or RCh administration of senktide by dual-label immunohistochemical detection of kisspeptin and c-Fos (i.e. marker of neuronal activation). We then administered the NK3R agonist, senktide, into the RCh of ewes in the follicular phase of the oestrous cycle and conducted frequent blood sampling during intracerebroventricular infusion of the kisspeptin receptor antagonist Kp-271 or saline. Our results show that the surge-like secretion of LH induced by RCh senktide administration coincided with a dramatic increase in c-Fos expression within arcuate nucleus (ARC) kisspeptin neurones, and was completely blocked by Kp-271 infusion. We substantiate these data with evidence of direct projections of RCh neurones to ARC kisspeptin neurones. Thus, NKB-responsive neurones in the RCh act to stimulate GnRH secretion by inducing kisspeptin release from KNDy neurones.
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: P
authors.initials: P
authors.lastname: Grachev
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Porter
authors.affiliation: Department of Neurobiology & Anatomical Sciences, The University of Mississippi Medical Center, Jackson, MS, USA.|Department of Physiology & Biophysics, The University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Coolen
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: McCosh
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Connors
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Hileman
authors.affiliation: Department of Neurobiology & Anatomical Sciences, The University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: M N
authors.initials: MN
authors.lastname: Lehman
authors.affiliation: Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Goodman
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology* / Q000502:physiology; D005260:Female; D057967:Infusions, Intraventricular; D059648:Kisspeptins / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D009474:Neurons / Q000502:physiology; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011301:Preoptic Area; D000074502:Receptors, Kisspeptin-1 / Q000037:antagonists & inhibitors; D018042:Receptors, Neurokinin-3 / Q000378:metabolism*; D012756:Sheep; D013373:Substance P / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: D059648:Kisspeptins; D010446:Peptide Fragments; D000074502:Receptors, Kisspeptin-1; D018042:Receptors, Neurokinin-3; C054724:senktide; D013373:Substance P; D007986:Luteinizing Hormone
keywords: KNDy neurones; LH surge; NK3R; kisspeptin; retrochiasmatic area; tachykinins