title: Hypotensive effects of neuromedin U microinjected into the cardiovascular-related region of the rat nucleus tractus solitarius.
abstract: Neuromedin U (NMU) is a brain-gut peptide with potent contractile effects on the uterus and smooth muscle. Intracerebroventricular injection of NMU reportedly decreased food intake and body-weight gain in the rat. We evaluated the effects of NMU delivered by microinjection into the rat nucleus tractus solitarius (NTS) on cardiovascular responses. At the concentrations used (5, 10 or 50 pmol), the intra-NTS injection of NMU in artificial cerebrospinal fluid produced a significant reduction in both the mean arterial pressure and heart rate. The hypotensive responses were dose dependent. Our findings suggest that NMU may act as a neurotransmitter or neuromodulative substance that causes excitation of neurons in the NTS and that it may play a role in cardiovascular regulation in vivo.
authors.affiliation: Department of Physiology, Wakayama Medical University, Wakayama City, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tsubota
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kakimoto
authors.forename: Kyoko
authors.initials: K
authors.lastname: Owada-Makabe
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yukawa
authors.forename: Xiang-Ming
authors.initials: XM
authors.lastname: Liang
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Mune
authors.forename: Masanobu
authors.initials: M
authors.lastname: Maeda
mesh_terms: D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007022:Hypotension / Q000139:chemically induced* / Q000503:physiopathology; D008297:Male; D008845:Microinjections; D009479:Neuropeptides / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D017552:Solitary Nucleus / Q000187:drug effects* / Q000502:physiology
chemical_list: D009479:Neuropeptides; C056900:neuromedin U