title: Defining Subpopulations of Arcuate Nucleus GABA Neurons in Male, Female, and Prenatally Androgenized Female Mice.
abstract: OBJECTIVE
  Arcuate nucleus (ARN) γ-aminobutyric acid (GABA) neurons are implicated in many critical homeostatic mechanisms, from food intake to fertility. To determine the functional relevance of ARN GABA neurons, it is essential to define the neurotransmitters co-expressed with and potentially co-released from ARN GABA neurons.
  
  
  METHODS
  The present study investigated the expression of markers of specific signaling molecules by ARN GABA neurons in brain sections from male, female, and, in some cases, prenatally androgen-treated (PNA) female, vesicular GABA transporter (VGaT)-ires-Cre/tdTomato reporter mice. Immunofluorescence for kisspeptin, β-endorphin, neuropeptide Y (NPY), tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS) was detected by confocal microscopy, and co-localization with tdTomato VGaT reporter expression throughout the ARN was quantified.
  
  
  RESULTS
  GABA neurons rarely co-localized with kisspeptin (<2%) or β-endorphin (<1%), and only a small proportion of kisspeptin (∼10%) or β-endorphin (∼3%) neurons co-localized with VGaT in male and female mice. In contrast, one-third of ARN GABA neurons co-localized with NPY, and nearly all NPY neurons (>95%) co-localized with VGaT across groups. Both TH and nNOS labeling was co-localized with ∼10% of ARN GABA neurons. The proportion of TH neurons co-localized with VGaT was significantly greater in males than either control or PNA females, and the proportion of nNOS neurons co-localizing VGaT was higher in control and PNA females compared with males.
  
  
  CONCLUSIONS
  These data highlight NPY as a significant subpopulation of ARN GABA neurons, demonstrate no significant impact of PNA on signal co-expression, and, for the first time, show sexually dimorphic co-expression patterns of TH and nNOS with ARN GABA neurons.
authors.affiliation: Centre for Neuroendocrinology, Department of Physiology, University of Otago School of Medical Sciences, Dunedin, New Zealand.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Marshall
authors.forename: Elodie
authors.initials: E
authors.lastname: Desroziers
authors.forename: Timothy
authors.initials: T
authors.lastname: McLennan
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Campbell
mesh_terms: D000728:Androgens / Q000008:administration & dosage / Q000378:metabolism; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology* / Q000502:physiology*; D002452:Cell Count; D005260:Female; D005455:Fluorescent Antibody Technique; D059330:GABAergic Neurons / Q000166:cytology* / Q000502:physiology*; D059648:Kisspeptins / Q000378:metabolism; D008297:Male; D008822:Mice, Transgenic; D009478:Neuropeptide Y / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D012727:Sex Characteristics; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism; D001615:beta-Endorphin / Q000378:metabolism
chemical_list: D000728:Androgens; D059648:Kisspeptins; D009478:Neuropeptide Y; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; D001615:beta-Endorphin; D052248:Nitric Oxide Synthase Type I; C496321:Nos1 protein, mouse; D014446:Tyrosine 3-Monooxygenase
keywords: Hypothalamus; Kisspeptin; Neuropeptide Y; Nitric oxide synthase; Polycystic ovary syndrome; Tyrosine hydroxylase