Effects of adrenomedullin 2 on regional hemodynamics in conscious rats.
The present study aimed to assess the effects of rat adrenomedullin 2 on systemic and regional hemodynamics in conscious Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Intravenous infusion of rat adrenomedullin 2 (0.25-5 micro g/kg/min) decreased blood pressure, and increased heart rate in a dose-dependent manner in both types of rats. Rat adrenomedullin 2 (5 micro g/kg/min) increased heart rate and cardiac output. As a result, total peripheral resistance significantly decreased. In SHRs, adrenomedullin 2 significantly increased regional blood flow in the heart, liver, spleen, kidneys, and adrenal glands. Especially, effects on heart, liver, and kidneys were remarkable. Regional hemodynamic changes were reproduced in WKY rats, and there was no qualitative difference in regional responses to rat adrenomedullin 2 between SHRs and WKY rats. Thus, rat adrenomedullin 2 predominantly increased flow rates in organs that were richly blood-supplied from cardiac output. Rat adrenomedullin 2 may contribute to the regulation of the cardiovascular system, by acting as a local vasodilatory hormone as well as a circulatory hormone.
Fujisawa
Yoshihide
Y
Life Science Center, School of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-Gun, Kagawa, Japan. recfuji@kms.ac.jp
Nagai
Yukiko
Y
Miyatake
Akira
A
Miura
Katsuyuki
K
Nishiyama
Akira
A
Kimura
Shoji
S
Abe
Youichi
Y
D053607:Adrenomedullin / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
C499411:Adm2 protein, rat; D009479:Neuropeptides; D053607:Adrenomedullin