Combined effect of cholesterol feeding and sympathectomy on the lipid content in rabbit aortas

There is indirect evidence that sympathetic innervation may have an effect on the metabolic rate of the vessel wall. to shed some light on this question, this investigation was designed to study whether or not diminished adrenergic nerve activity in the arterial wall leads to greater susceptibility to atherosclerosis. A total of 48 rabbits was studied of which, 26 were chemically sympathectomized. Both groups of rabbits were subdivided further into a group fed regular rabbit chow and a group fed regular rabbit chow containing 1% cholesterol. Both groups, control and 6-hydroxydopamine (6-OHDA) treated, had similar plasma lipids as well as the lipid content in their aortae. After 80 days of 1% cholesterol dietary supplement the plasma lipids rose gradually with no significant difference between controls and 6-OHDA-treated animals. The aortas of sympathectomized rabbits contained significantly more cholesterol and total lipids than those from fully innervated controls. It is concluded that the the reduction of a continuous barrage of sympathetic nervous impulses to the arterial wall modifies its metabolism. In combination with additional exogenous influences, e.g. high cholesterol intake, the sympathectomized arteries become more susceptible to lipid accumulation.