“…Despite numerous studies, the interrelation between the vegetative nervous system, i. e., catecholamine metabolism and the renin-angiotensin system, is not yet clear. A recent study [3] shows the changes in the basic autonomic control following stereotaxic subthalomotomy in the zona incerta. Therefore any changes regarding the PRA level in the blood after a stereotaxic operation might help to bring out this relationship.…”