Changes in Femoral Artery Blood Flow and Supersensitivity of Arteries to Norepinephrine After Lumbar Sympathectomy in Dogs

Abstract

Blood flow of the femoral arteries of both sides was measured, and changes in sensitivity of the arteries to norepinephrine were studied in unilateral sym pathectomized canine hindlimbs, in order to demonstrate the presence of super sensitivity of arteries to norepinephrine after sympathectomy. Before injections of norepinephrine into the vein, the ratio of blood flow in the femoral artery on the sympathectomized side to that on the opposite side increased in L3-L5 and in L3-L7 sympathectomized hindlimbs. This ratio of blood flow decreased in inverse proportion to the increase of doses of norepinephrine admin istered into the vein in both groups, and finally the flow on the sympathectomised side became lower than that on the nonsympathectomized side. The dorsal pedal arteries on the L3-L5 sympathectomized side, which are subject to decentralization but not denervation, had a slight degree of supersen sitivity to norepinephrine. The saphenous arteries on the L3-L5 sym pathectomized side were incompletely denervated and showed a moderate degree of supersensitivity to norepinephrine. The saphenous and the dorsal pedal arteries on the L3-L7 sympathectomized side were denervated almost completely and showed a significant increase in sensitity to norepinephrine. These results provide evidence that supersensitivity to norepinephrine does occur in the arteries of sympathectomized canine hindlimbs.