Distribution of vesicular glutamate transporter mRNA in rat hypothalamus.
Two isoforms of the vesicular glutamate transporter, VGLUT1 and VGLUT2, were recently cloned and biophysically characterized. Both VGLUT1 and VGLUT2 specifically transport glutamate into synaptic vesicles, making them definitive markers for neurons using glutamate as a neurotransmitter. The present study takes advantage of the specificity of the vesicular transporters to afford the first detailed map of putative glutamatergic neurons in the rat hypothalamus. In situ hybridization analysis was used to map hypothalamic distributions of VGLUT1 and VGLUT2 mRNAs. VGLUT2 is clearly the predominant vesicular transporter mRNA found in the hypothalamus; rich expression can be documented in regions regulating energy balance (ventromedial hypothalamus), neuroendocrine function (preoptic nuclei), autonomic tone (posterior hypothalamus), and behavioral/homeostatic integration (lateral hypothalamus, mammillary nuclei). Expression of VGLUT1 is decidedly more circumspect and is confined to relatively weak labeling in lateral hypothalamic regions, neuroendocrine nuclei, and the suprachiasmatic nucleus. Importantly, dual-label analysis revealed no incidence of colocalization of VGLUT1 or VGLUT2 mRNAs in glutamic acid decarboxylase (GAD) 65-positive neurons, indicating that GABA neurons do not express either transporter. Our data support a major role for hypothalamic glutamatergic neurons in regulation of all aspects of hypothalamic function.
Department of Psychiatry, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0559, USA.
Dana R
DR
Ziegler
William E
WE
Cullinan
James P
JP
Herman
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D005968:Glutamate Decarboxylase / Q000235:genetics; D018698:Glutamic Acid / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D026901:Membrane Transport Proteins; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000033:anatomy & histology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; D033921:Vesicular Transport Proteins
D015415:Biomarkers; D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; C493475:Slc17a6 protein, rat; C493466:Slc17a7 protein, rat; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; D033921:Vesicular Transport Proteins; D018698:Glutamic Acid; D005968:Glutamate Decarboxylase