AJP - Heart and Circulatory Physiology, Vol 235, Issue 5 587-H591, Copyright © 1978 by American Physiological Society
Dextran as a radioactive microsphere suspending agent: severe hypotensive effect in rat
S. F. Flaim, Z. Q. Morris and T. J. Kennedy
The effects of different commercially available radioactive microsphere
suspending solutions were studied on the cardiovascular hemodynamics of
male, Sprague-Dawley rats. Single left ventricular injections of carbonized
radioactive microspheres (15 +/- 5 micron diam) totaling 850,000 spheres,
suspended in 10% dextran (mol wt, 73,000) solution with Tween, caused
reductions in arterial pressure (control, 101; postinjection, 74 mmHg; P
less than 0.001), with no change in heart rate. Identical injections made
with isotonic saline solution plus Tween had no effect on either heart rate
or arterial pressure. Independent studies were conducted to examine the
effects of 1-ml injections of four suspending solutions without
microspheres on the cardiovascular hemodynamics of rats. Isotonic saline
had no hemodynamic effect, and isotonic saline plus Tween decreased only
heart rate. Ten percent dextran soluton with Tween decreased arterial
pressure, heart rate, peak left ventricular systolic pressure, and left
ventricular end-diastolic pressure. Similar changes occurred when dextran
solution without Tween was administered. These data demonstrate that 10%
dextran solution used as a microsphere suspending agent induces a severe
hypotensive response in rats. Furthermore, injections of up to 850,000
microspheres in isotonic saline solution do not alter arterial pressure in
the rat.
