title: Heterogeneous expression of the potassium-chloride cotransporter KCC2 in gonadotropin-releasing hormone neurons of the adult mouse.
abstract: In mature central neurons, chloride extrusion mediated by the K-Cl cotransporter KCC2 appears to be largely responsible for the Cl(-) driving force that allows gamma-aminobutyric acid(A) (GABA(A)) receptor activation to trigger a hyperpolarization. In its absence, GABA's effect is typically depolarizing and often excitatory. We examined the colocalization of KCC2 and GnRH in adult male and female mice using a combined in situ hybridization-immunofluorescence procedure. We found that KCC2 was localized to approximately 34% of GnRH neurons. This proportion was similar in females and males. However, females exhibited a marked rostrocaudal gradient of colocalization that was not seen in males. By contrast, KCC2 was localized to nearly all vasopressin neurons of the supraoptic nucleus. These results indicate that a substantial fraction of GnRH neurons may be depolarized and excited by GABA(A) receptor activation throughout life, supporting the existence of functionally heterogeneous subpopulations.
authors.affiliation: Reproductive Endocrine Unit, BHX-519, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA. leupen@world.oberlin.edu
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Leupen
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Tobet
authors.forename: W F
authors.initials: WF
authors.lastname: Crowley
authors.forename: Kai
authors.initials: K
authors.lastname: Kaila
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D011963:Receptors, GABA-A / Q000032:analysis / Q000235:genetics*; D027981:Symporters / Q000032:analysis / Q000235:genetics*; D005680:gamma-Aminobutyric Acid / Q000502:physiology; D000096922:K Cl- Cotransporters
chemical_list: D007987:Gonadotropin-Releasing Hormone; D011963:Receptors, GABA-A; D027981:Symporters; D005680:gamma-Aminobutyric Acid; D000096922:K Cl- Cotransporters