Quantitative Changes in Foot Blood Flow in the Dog Following Sympathectomy and Motor Denervation

¹ From the Department of Physiology and Pharmacology, University of North Dakota School of Medicine, Grand Forks, North Dakota

In dogs with unilateral lumbar sympathectomy blood flows were higher in the operated foot for about 3 days; later this foot had lower flows under anesthesia. Vasodilator drugs given intravenously or intra-arterially increased blood flow in the chronically sympathectomized foot, indicating that anatomical narrowing was not significant in the vessels. Temperature studies showed that the normal foot became warmer under anesthesia, but this was not true of the operated foot. Similar results were found following chronic motor denervation of the foot. These experiments suggest that the sympathectomized or denervated foot vessels were constricted by some circulating substance that was less effective on normal vessels.