Chemical sympathectomy by 6-hydroxydopamine and arterial enzymes and lactate in the rabbit

The effect of 6-hydroxydopamine (6-OHDA) on the activity of arterial enzymes and lactate was investigated in rabbits. It is known that 6-OHDA exerts a specific damaging effect on the adrenergic nerve endings and produces gangliopetal degeneration, thus eliminating the adrenergic effect pathway. Eight weeks following chemical sympathectomy malate dehydrogenase, isocitrate dehydrogenase, lipoamide dehydrogenase, and creatine phosphokinase exhibited significantly lower activity in the iliofemoral arteries of the 6-OHDA-treated animals as compared to those of the control rabbits. A direct inhibition of the activity of the enzymes by 6-OHDA can be reasonably excluded on the basis of in vitro studies. The aortas of the 6-OHDA-treated animals revealed an increase of pyruvate kinase only, without any significant change in activity of the other enzymes studied. The results dealing with enzymes in the iliofemoral arteries resemble the findings obtained previously in injured or atherosclerotic or “preatherosclerotic” human and animal arteries. The lactate level in the abdominal aortas, which are structurally similar to the iliofemoral arteries, was significantly higher in the 6-OHDA-treated animals than in the control rabbits. It appears that alterations of arterial innervation produce a metabolic pattern which may contribute to increased susceptibility to atherosclerosis.