| First Author | Negishi K | Year | 2020 |
| Journal | J Comp Neurol | Volume | 528 |
| Issue | 11 | Pages | 1833-1855 |
| PubMed ID | 31950494 | Mgi Jnum | J:351535 |
| Mgi Id | MGI:7627187 | Doi | 10.1002/cne.24857 |
| Citation | Negishi K, et al. (2020) Distributions of hypothalamic neuron populations coexpressing tyrosine hydroxylase and the vesicular GABA transporter in the mouse. J Comp Neurol 528(11):1833-1855 |
| abstractText | The hypothalamus contains catecholaminergic neurons marked by the expression of tyrosine hydroxylase (TH). As multiple chemical messengers coexist in each neuron, we determined if hypothalamic TH-immunoreactive (ir) neurons express vesicular glutamate or GABA transporters. We used Cre/loxP recombination to express enhanced GFP (EGFP) in neurons expressing the vesicular glutamate (vGLUT2) or GABA transporter (vGAT), then determined whether TH-ir neurons colocalized with native EGFP(Vglut2) - or EGFP(Vgat) -fluorescence, respectively. EGFP(Vglut2) neurons were not TH-ir. However, discrete TH-ir signals colocalized with EGFP(Vgat) neurons, which we validated by in situ hybridization for Vgat mRNA. To contextualize the observed pattern of colocalization between TH-ir and EGFP(Vgat) , we first performed Nissl-based parcellation and plane-of-section analysis, and then mapped the distribution of TH-ir EGFP(Vgat) neurons onto atlas templates from the Allen Reference Atlas (ARA) for the mouse brain. TH-ir EGFP(Vgat) neurons were distributed throughout the rostrocaudal extent of the hypothalamus. Within the ARA ontology of gray matter regions, TH-ir neurons localized primarily to the periventricular hypothalamic zone, periventricular hypothalamic region, and lateral hypothalamic zone. There was a strong presence of EGFP(Vgat) fluorescence in TH-ir neurons across all brain regions, but the most striking colocalization was found in a circumscribed portion of the zona incerta (ZI)-a region assigned to the hypothalamus in the ARA-where every TH-ir neuron expressed EGFP(Vgat) . Neurochemical characterization of these ZI neurons revealed that they display immunoreactivity for dopamine but not dopamine beta-hydroxylase. Collectively, these findings indicate the existence of a novel mouse hypothalamic population that may signal through the release of GABA and/or dopamine. |
