Neuropeptide Y Innervation and Neuropeptide-Y-Y1-Receptor-Expressing Neurons in the Paraventricular Hypothalamic Nucleus of the Mouse

Vol. 70, No. 5, 1999

Free Abstract Article (Fulltext) Article (PDF 644 KB)

Functional Neuroanatomy of Hypothalamic Neurons

Neuropeptide Y Innervation and Neuropeptide-Y-Y1-Receptor-Expressing Neurons in the Paraventricular Hypothalamic Nucleus of the Mouse
Christian Broberger^a, Theo J. Visser^b, Michael J. Kuhar^c, Tomas Hökfelt^a

^aDepartment of Neuroscience, Karolinska Institutet, Stockholm, Sweden;
^bDepartment of Internal Medicine III, Erasmus University Medical School, Rotterdam, The Netherlands;
^cYerkes Regional Primate Research Center, Emory University, Atlanta, Ga., USA

Address of Corresponding Author

Neuroendocrinology 1999;70:295-305 (DOI: 10.1159/000054490)

Key Words

Agouti gene-related protein
Cocaine- and amphetamine-regulated transcript
Corticotropin-releasing hormone
Feeding
Magnocellular neurons
Oxytocin
Parvocellular neurons
Thyrotropin-releasing hormone
Vasopressin
Mouse

Abstract

The paraventricular hypothalamic nucleus (PVH) serves as integrator and link between the neuroendocrine and autonomic nervous systems. Neuropeptide-Y (NPY)-producing neurons in the arcuate nucleus project to the PVH, where neurons expressing NPY Y1 receptor (Y1R) have been demonstrated. This projection has been suggested to be involved in the regulation of parameters related to energy metabolism, e.g. food intake and thermoregulation. The present study aimed at characterizing this pathway and chemically defining Y1R-expressing neurons by means of immunohistochemistry. The densely distributed NPY-immunoreactive (ir) terminals in the PVH co-stained for agouti gene-related protein (AGRP) mainly in the medial parvocellular regions, indicating an origin in the arcuate nucleus. This was in contrast to noradrenergic/adrenergic terminals in the PVH, which were less frequently seen to contain NPY-like immunoreactivity. Furthermore, AGRP-ir terminals were seen forming abundant close appositions on Y1R-ir cell bodies. Double staining revealed co-existence of Y1R-like immunoreactivity and immunoreactivities for thyrotropin-releasing hormone (TRH) and, to a minor extent, cocaine- and amphetamine-regulated transcript peptide in parvocellular neurons. No Y1R-like immunoreactivity was noted in parvocellular neurons expressing corticotropin-releasing hormone or in magnocellular neurons expressing vasopressin or oxytocin. The present results suggest that the arcuatoparaventricular NPY projection targets the TRH neurons preferentially via the Y1R, whereas the NPYergic regulation of corticotropinergic and magnocellular neurons may be relayed through other subtypes of NPY receptors. This study further defines the link between NPY-induced feeding and the hypothalamus-pituitary-thyroid axis.

Author Contacts

Christian Broberger
Department of Neuroscience, Doktorsringen 12B
Karolinska Institutet, SE-171 77 Stockholm (Sweden)
Tel. +46 8 7287070, Fax +46 8 33 16 92
E-Mail Christian.Broberger@neuro.ki.se

Article Information

Received: Received: April 29, 1999
Accepted after revision: August 2, 1999
Number of Print Pages : 11
Number of Figures : 5, Number of Tables : 0, Number of References : 71

Special Subscription Offer
for INF Members!

This journal is part of the first subject package of the Karger

Journal Archive Collection

Information on packages (PDF)
Free sample issues

For non-native English speakers and international authors who would like assistance with their writing before submission, we suggest American Journal Experts for their research paper editing service.