title: Kisspeptin neurons co-express met-enkephalin and galanin in the rostral periventricular region of the female mouse hypothalamus.
abstract: It is now well established that the kisspeptin neurons of the hypothalamus play a key role in regulating the activity of gonadotropin-releasing hormone (GnRH) neurons. The population of kisspeptin neurons residing in the rostral periventricular region of the third ventricle (RP3V), encompassing the anteroventral periventricular (AVPV) and periventricular preoptic nuclei (PVpo), are implicated in the generation of the preovulatory GnRH surge mechanism and puberty onset in female rodents. The present study examined whether these kisspeptin neurons may express other neuropeptides in the adult female mouse. Initially, the distribution of galanin, neurotensin, met-enkephalin (mENK), and cholecystokinin (CCK)-immunoreactive cells was determined within the RP3V of colchicine-treated mice. Subsequent experiments, using a new kisspeptin-10 antibody raised in sheep, examined the relationship of these neuropeptides to kisspeptin neurons. No evidence was found for expression of neurotensin or CCK by RP3V kisspeptin neurons, but subpopulations of kisspeptin neurons were observed to express galanin and mENK. Dual-labeled RP3V kisspeptin/galanin cells represented 7% of all kisspeptin and 21% of all galanin neurons whereas dual-labeled kisspeptin/mENK cells represented 28-38% of kisspeptin neurons and 58-68% of the mENK population, depending on location within the AVPV or PVpo. Kisspeptin neurons in the arcuate nucleus were also found to express galanin but not mENK. These observations indicate that, like the kisspeptin population of the arcuate nucleus, kisspeptin neurons in the RP3V also co-express a range of neuropeptides. This pattern of co-expression should greatly increase the dynamic range with which kisspeptin neurons can modulate the activity of their afferent neurons.
authors.affiliation: Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Medical Sciences, Dunedin 9054, New Zealand.
authors.forename: Robert
authors.initials: R
authors.lastname: Porteous
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Petersen
authors.forename: Shel Hwa
authors.initials: SH
authors.lastname: Yeo
authors.forename: Janardhan P
authors.initials: JP
authors.lastname: Bhattarai
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciofi
authors.forename: Xavier D'anglemont
authors.initials: XD
authors.lastname: de Tassigny
authors.forename: William H
authors.initials: WH
authors.lastname: Colledge
authors.forename: Alain
authors.initials: A
authors.lastname: Caraty
authors.forename: Allan E
authors.initials: AE
authors.lastname: Herbison
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000737:chemistry / Q000378:metabolism; D004744:Enkephalin, Methionine / Q000096:biosynthesis*; D005260:Female; D019004:Galanin / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D007031:Hypothalamus / Q000737:chemistry / Q000378:metabolism*; D059648:Kisspeptins / Q000096:biosynthesis*; D051379:Mice; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D020542:Third Ventricle / Q000737:chemistry / Q000378:metabolism
chemical_list: D059648:Kisspeptins; D004744:Enkephalin, Methionine; D019004:Galanin