Kouichiro Minami1,*, Kayoko Segawa2, Yasuhito Uezono3, Yosuke Shiga1, Munehiro Shiraishi1, Junichi Ogata1 and Akio Shigematsu1
1Department of Anesthesiology and 2Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu 807-8555, Japan
3Department of Pharmacology, Miyazaki Medical College, School of Medicine, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
*Corresponding author. FAX: +81-93-601-2910, E-mail: email@example.com
Abstract: Adrenomedullin (AM), a hypotensive peptide originally isolated from human pheochromocytoma, has been reported to regulate renal functions. In patients with glomerulonephritis, the serum levels of AM are elevated as well as hypertensive agents norepinephrine (NE) and angiotensin II (AII). The effects of AM on the NE- or AII-induced pressor effects and renal blood flow responses, however, are not well clarified. We examined the effects of AM on blood pressure and renal blood flow induced by NE or AII in anesthetized rats. Arterial blood pressure and renal blood flow were measured using a calibrated pressure transducer and a laser Doppler flowmeter, respectively. Drugs were injected into the tail vein with a syringe. Intravenous administration of AM (1 - 3 nmol/kg) decreased the arterial blood pressure in anesthetized rats in a dose-dependent manner, whereas it did not affect the renal blood flow. NE or AII administration in anesthetized rats caused both increases in blood pressure and decreases in renal blood flow. Simultaneous administration of AM with NE or AII prevented the increasing effects of blood pressure and inhibited the decreases in renal blood flow caused by NE or AII. These findings suggest that AM may have a protective role against the pressor effects and decrease in renal blood flow caused by NE or AII.
Keywords: Adrenomedullin, Renal blood flow, Norepinephrine, Angiotensin II
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