Autor: |
Eppel, Gabriela A., Jacono, David Lo, Shirai, Mikiyasu, Umetani, Keiji, Evans, Roger G., Pearson, James T. |
Předmět: |
|
Zdroj: |
American Journal of Physiology: Renal Physiology; May2009, Vol. 296, pF1023-F1031, 9p, 2 Diagrams, 1 Chart, 2 Graphs |
Abstrakt: |
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). lodinated 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 2Hz. 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 p.m. 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. [ABSTRACT FROM AUTHOR] |
Databáze: |
Complementary Index |
Externí odkaz: |
|