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This Article Full Text Full Text (PDF) All Versions of this Article: 296/5/F1023    most recent 90499.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Eppel, G. A. Articles by Pearson, J. T. Search for Related Content PubMed PubMed Citation Articles by Eppel, G. A. Articles by Pearson, J. T.

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Departments of ¹Physiology and ²Mechanical and Aerospace Engineering, Monash University, Melbourne, Australia; ³Department of Clinical Radiology, Hiroshima International University, Hiroshima; ⁴Japan Synchrotron Radiation Research Institute, Hyogo, Japan; and ⁵Monash Centre for Synchrotron Science, Monash University, Melbourne, Australia

Submitted 20 August 2008 ; accepted in final form 27 February 2009

We have developed a new method for contrast microangiography of the rat renal circulation using synchrotron radiation. The method was applied to determine responses of the renal arterial vasculature to angiotensin II and electrical stimulation of the renal nerves (RNS). Iodinated contrast agent was administered directly into the renal artery of pentobarbital-anesthetized rats before and during 1) intravenous infusion of angiotensin II (1.6 µg·kg^–1·min^–1) or 2) its vehicle, or 3) RNS at 2 Hz. Images were obtained at 30 Hz, before and during these treatments, and vascular caliber was determined by use of a newly developed algorithm described herein. Up to four levels of branching could be observed simultaneously along the arterial tree, comprising vessels with resting diameter of 28–400 µm. Vessel diameter was not significantly altered by vehicle infusion (+3.1 ± 3.5% change) but was significantly reduced by angiotensin II (–24.3 ± 3.4%) and RNS (–17.1 ± 3.8%). Angiotensin II-induced vasoconstriction was independent of vessel size, but RNS-induced vasoconstriction was greatest in vessels with a resting caliber of 100–200 µm and least in vessels with a resting caliber 40–100 µm. In conclusion, the method we describe herein provides a new approach for assessing responses of the renal arterial circulation to vasoactive factors along several orders of branching.

angiography; angiotensin II; vascular caliber; kidney circulation; renal nerves