Cardiovascular actions of central neuromedin U in conscious rats.
Neuromedin U (NMU) is a brain-gut peptide, which peripherally stimulates smooth muscle, increases of blood pressure, alters ion transport in the gut, controls local blood flow, and regulates adrenocortical function. Although intracerebroventricular (i.c.v.) administration of NMU is known to decrease food intake and body weight, little is known about its effect on other physiological functions. We examined the effects of i.c.v. administration of NMU on mean arterial pressure (MAP), heart rate (HR), and plasma norepinephrine in conscious rats. Neuromedin U (0.05 and 0.5 nmol) provoked an increase in MAP (93.8 +/- 0.5 to 123.5 +/- 1.7 and 94.7 +/- 0.8 to 132.7 +/- 3.0 mm Hg, respectively) and HR (334.9 +/- 6.0 to 494.1 +/- 6.9 and 346.3 +/- 3.3 to 475.1 +/- 8.9 beats/min, respectively). In contrast, plasma norepinephrine increased only with a high dose of neuromedin U. Intravenously administered NMU (0.5 nmol) elicited a small and short lasting increase in MAP, compared to that by i.c.v. NMU. These results indicate that central neuromedin U regulates sympathetic nervous system activity and affects cardiovascular function.
Chu
Chunping
C
Department of Physiology, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan.
Jin
Qinghua
Q
Kunitake
Takato
T
Kato
Kazuo
K
Nabekura
Takashi
T
Nakazato
Masamitsu
M
Kangawa
Kenji
K
Kannan
Hiroshi
H
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D003243:Consciousness; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D009479:Neuropeptides; C056900:neuromedin U; D009638:Norepinephrine