Faculty Collaboration Database

Forebrain origins of glutamatergic innervation to the rat paraventricular nucleus of the hypothalamus: differential inputs to the anterior versus posterior subregions. J Comp Neurol 2011 May 01;519(7):1301-19

Date

04/01/2011

Pubmed ID

21452198

Pubmed Central ID

PMC3893028

DOI

10.1002/cne.22571

Scopus ID

2-s2.0-79953152521 (requires institutional sign-in at Scopus site)   67 Citations

Abstract

The hypothalamic paraventricular nucleus (PVN) regulates numerous homeostatic systems and functions largely under the influence of forebrain inputs. Glutamate is a major neurotransmitter in forebrain, and glutamate neurosignaling in the PVN is known to mediate many of its functions. Previous work showed that vesicular glutamate transporters (VGluTs; specific markers for glutamatergic neurons) are expressed in forebrain sites that project to the PVN; however, the extent of this presumed glutamatergic innervation to the PVN is not clear. In the present study retrograde FluoroGold (FG) labeling of PVN-projecting neurons was combined with in situ hybridization for VGluT1 and VGluT2 mRNAs to identify forebrain regions that provide glutamatergic innervation to the PVN and its immediate surround in rats, with special consideration for the sources to the anterior versus posterior PVN. VGluT1 mRNA colocalization with retrogradely labeled FG neurons was sparse. VGluT2 mRNA colocalization with FG neurons was most abundant in the ventromedial hypothalamus after anterior PVN FG injections, and in the lateral, posterior, dorsomedial, and ventromedial hypothalamic nuclei after posterior PVN injections. Anterograde tract tracing combined with VGluT2 immunolabeling showed that 1) ventromedial nucleus-derived glutamatergic inputs occur in both the anterior and posterior PVN; 2) posterior nucleus-derived glutamatergic inputs occur predominantly in the posterior PVN; and 3) medial preoptic nucleus-derived inputs to the PVN are not glutamatergic, thereby corroborating the innervation pattern seen with retrograde tracing. The results suggest that PVN subregions are influenced by varying amounts and sources of forebrain glutamatergic regulation, consistent with functional differentiation of glutamate projections.

Author List

Ulrich-Lai YM, Jones KR, Ziegler DR, Cullinan WE, Herman JP

Author

William E. Cullinan PhD Adjunct Associate Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Fluorescent Dyes
Glutamic Acid
Immunohistochemistry
Male
Neural Pathways
Paraventricular Hypothalamic Nucleus
Prosencephalon
Rats
Rats, Sprague-Dawley
Stilbamidines
Vesicular Glutamate Transport Protein 1
Vesicular Glutamate Transport Protein 2