Centrally administered neuromedin U activates neurosecretion and induction of c-fos messenger ribonucleic acid in the paraventricular and supraoptic nuclei of rat.
We examined the effects of intracerebroventricular (icv) administration of neuromedin U (NMU) on plasma arginine vasopressin (AVP), oxytocin (OXT), and ACTH in rats, using RIA. The induction of c-fos protein (Fos) was examined by immunohistochemical study, and in situ hybridization histochemistry was used to detect c-fos gene expression in the paraventricular (PVN) and supraoptic nuclei (SON). Plasma AVP, OXT, and ACTH were increased in a dose-related manner 15 min after icv administration of NMU. The icv administration of NMU caused a marked induction of Fos-like immunoreactivity (LI) in the SON and the magnocellular and parvocellular divisions of the PVN. In the SON and the magnocellular divisions of the PVN, OXT-LI cells predominantly exhibited nuclear Fos-LI in comparison with AVP-LI cells. The marked induction of the expression of c-fos gene in the PVN and SON was observed 15, 30, and 60 min after icv administration of NMU. Neurosecretion and induction of c-fos gene expression after centrally administered NMU were significantly reduced by pretreatment with anti-NMU IgG. These results suggest that centrally administered NMU activates OXTergic cells in the PVN and SON predominantly as well as hypothalamo-pituitary adrenal axis.
Ozaki
Yumi
Y
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Onaka
Tatsushi
T
Nakazato
Masamitsu
M
Saito
Jun
J
Kanemoto
Keiko
K
Matsumoto
Tetsuro
T
Ueta
Yoichi
Y
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001127:Arginine Vasopressin / Q000032:analysis / Q000097:blood; D003345:Corticosterone / Q000097:blood; D015870:Gene Expression; D006651:Histocytochemistry; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D008297:Male; D009479:Neuropeptides / Q000008:administration & dosage*; D010121:Oxytocin / Q000032:analysis / Q000097:blood; D010286:Paraventricular Hypothalamic Nucleus / Q000737:chemistry / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013495:Supraoptic Nucleus / Q000737:chemistry / Q000378:metabolism*
D009479:Neuropeptides; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D001127:Arginine Vasopressin; C056900:neuromedin U; D010121:Oxytocin; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone