Arteriole response to 10 nM Angiotensin II

Angiotensin II has direct effects on renal vascular smooth muscle cells causing vasoconstriction of both the afferent and efferent arterioles which results in reduced renal blood flow.  The movie illustrates the efferent arteriole response to 10 nM angiotensin II.  This movie was prepared from research conducted in my laboratory using the mouse in vitro blood perfused juxtamedullary nephron technique.  This experimental tool allows for the real time analysis of direct measurements of renal arteriolar diameter during bath application of angiotensin II in the isolated perfused mouse kidney.  The efferent arteriole diameter measures 20.0 microns under baseline conditions.  Angiotensin II (10 nM) was applied to the surface of the kidney at the 15 min time point.  The efferent arteriole diameter measures 8.0 microns at the peak contraction to angiotensin II which occurred 30 seconds after application of the peptide.  This rapid and potent vasoconstriction represents a 60% reduction in vessel diameter.  At the 15:30 time point, the arteriole has narrowed to the point that single red blood cells can be seen traveling within the vessel.  During the steady state contraction to angiotensin II, the efferent arteriole diameter was reduced by 30% of the control diameter.  Upon removal of the peptide from the bath, the efferent arteriole diameter returned to the baseline diameter of 20 microns.