The effect of lumbar sympathectomy on postsynaptic vascular smooth muscle response in the lower limb in dogs.

The intent of this experiment was to study the postsynaptic vasoactive response to tolazoline hydrochloride and sodium-meglumine diatrizoate (Renografin-76) after a unilateral lumbar sympathectomy in a dog model. Both lower extremities were examined using the video dilution technique before and 1-2 weeks after unilateral lumbar sympathectomy (SE). Results showed (1) resting blood flow in the femoral artery as a percentage of cardiac output did not change after sympathectomy (mean and SD before and after SE: 7.0% +/- 2.3 and 6.0% +/- 2.9 respectively n = 13); (2) the reactive hyperemia in the femoral artery caused by sodium-meglumine diatrizoate (Renografin-76) was unchanged after sympathectomy; (3) the vasodilator effect of tolazoline hydrochloride decreased significantly after sympathectomy (p less than 0.05).