1995 Fiscal Year Final Research Report Summary
Assessment of intrarenal blood flow distribution and sodium excretion using contrast ultrasonography
| Project/Area Number |
06671142
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Kidney internal medicine
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| Research Institution | Kagawa Medical School |
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Principal Investigator |
YUASA Shigekazu Kagawa Medical School, The Second Department of Internal Medicine, Associate Professor, 医学部, 助教授 (60174827)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Norihiro Kagawa Medical School, The Second Department of Internal Medicine, Research Asso, 医学部附属病院, 助手 (70253268)
SUMIKURA Tohru Kagawa Medical School, The Second Department of Internal Medicine, Research Asso, 医学部, 助手 (40231378)
SENDA Shoichi Kagawa Medical School, The Department of Integrated Medicine, Associate Professo, 医学部附属病院, 助教授 (30145049)
MATSUO Hirohide Kagawa Medical School, The Second Department of Internal Medicine, Professor, 医学部, 教授 (90028514)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Contrast ultasonography / Intrarenal blood flow distribution / Total renal blood flow / Saline natriuresis / Pressure natriuresis / Endothelium-derived nitric oxide / Angiotensin II / Angiotensin II receptor antagonist |
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| Research Abstract |
The importance of the distribution of intrarenal blood flow in the regulation of various renal functions, such as urine concentration and sodium excretion, has been well recognized. However, there have been no reliable methods to measure local blood flow in the kidney in vivo. We studied the correlations between regional renal Blood flow and sodium excretion in vivo using contrast ultrasonograpy combined with intraaortic injection of a sonicated 5% albumin in mongrel dogs. Satisfactory sonographic enhancement in renal parenchyma was obtained by the sonicated 5% albumin of 0.15-0.25ml/kg. Furthermore, the inner/outer renal cortex ratio of peak intensity significantly increased during the intrarenal acetylcholine infusion. Intravenous infusion of nitric oxide (NO) synthesis inhibitor, N^G-nitro-L-arginine methyl ester (L-NAME), at a low dose significantly inhibited the natriuretic response to acte extracellular volume expansion with isotonic saline without altering total renal plasma flow and the distribution of renal cortical blood flow. This inhibitory effect of L-NAME was completely abolished by the pretreatment with angiotensin II receptor (AT_1) antagonist, L-158,809, suggesting an angiotensin II dependency of the reduced renal excretory response to acute extracellular volume expansion during NO synthesis inhibition.
In addition, we obtained effective signal enhancement in color Doppler flow imaging in the kidney with an intravenous injection of the contrast agent consisting of galactose/palmitic acid in patients with renal vascular or parenchymal diseases. Thus, these results suggest that the correlations between regional renal blood flow and sodium excretion can be detected by a quantitative analysis of signal enhancement in humans.
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