Neuropeptide Y activates urocortin 1 neurons in the nonpreganglionic Edinger-Westphal nucleus.
Central regulatory pathways promoting stress adaptation utilize various neurotransmitters/neuropeptides, such as urocortin 1 (Ucn1) and neuropeptide Y (NPY). Ucn1 is abundantly expressed in the nonpreganglionic Edinger-Westphal nucleus (npEW), where it is codistributed with NPY-immunoreactive (ir) terminals. A special role for both neuropeptides has been postulated in stress adaptation. Using double-labeling immunohistochemistry, we observed close appositions between NPY-ir terminals and neurons immunoreactive for Ucn1 in the rat, as well as in the human npEW. Therefore, we hypothesized that NPY might control the activity of Ucn1-positive neurons in the npEW. To test this hypothesis, NPY was injected into the lateral cerebral ventricle of rats, resulting in a strong activation of npEW Ucn1 neurons as revealed by Fos immunohistochemistry. Ucn1 mRNA was also upregulated in the npEW 2 hours after the injection of NPY. In a search for the type of NPY receptor that mediates this NPY-induced recruitment of npEW-Ucn1 cells, we found that the great majority of Ucn1 cells exhibited NPY Y5 receptor immunoreactivity, and only a few of the Ucn1 cells coexpressed the Y1 receptor. We concluded that NPY, via NPY Y5 and to a lesser extent via the Y1 receptors, exerts a stimulatory action on Ucn1 cells in the npEW. Further studies are currently in progress to elucidate the significance of this NPY-Ucn1 interaction in the npEW.
Gaszner
Balázs
B
Department of Anatomy, Medical Faculty, Pécs University and Neurohumoral Regulations Research Group of Hungarian Academy of Sciences, H-7643 Pécs, Szigeti út 12, Hungary.
Korosi
Anikó
A
Palkovits
Miklós
M
Roubos
Eric W
EW
Kozicz
Tamás
T
D000223:Adaptation, Psychological / Q000502:physiology; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000378:metabolism; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D017476:Receptors, Neuropeptide Y / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism; D013681:Tegmentum Mesencephali / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation; D054832:Urocortins
D009478:Neuropeptide Y; D012333:RNA, Messenger; D017476:Receptors, Neuropeptide Y; D054832:Urocortins; C100568:neuropeptide Y5 receptor; D003346:Corticotropin-Releasing Hormone