Denervation of Carotid Sinuses and Section of Depressor Nerves to Produce Chronic Arterial Hypertension

From the investigations of Hering, Heymans 1 and their collaborators 2 on the reflexes originating in the carotid sinuses came a method that promised to make possible the study of the pathological changes which may result from chronic, arterial hypertension, uncomplicated by the action of infectious or toxic agents. By denervating the carotid sinuses and sectioning the depressor nerves (rabbit) or the vagi (dog) these authors obtained the equivalent of a permanently low intracarotid pressure, namely, permanent arterial hypertension, hyperpnea, and hyperepinephrinemia. The hypertension was apparently demonstrated to be the direct result of the increased secretion of epinephrine. Unless the denervation wras performed in stages, the animal was said to succumb to acute cardiac dilatation. The respiratory effects of the denervation consisted of rapid, labored breathing with lowering of the alveolar CO₂.

The method was applied to the investigation of essential hypertension and arteriosclerosis with interesting and apparently positive results.

Experiments were planned to determine precisely the course of the blood pressure after denervation of the carotid sinuses and section of the depressor nerves, and to explore the possibilities in the operation for the production of lesions in the rabbit. Fourteen rabbits were successfully denervated either on one or both sides. Ten animals were operated upon in 2 stages, the second following the first by an interval of 5 to 10 days. Four animals were denervated in one stage. Blood pressure determinations by the McGregor 3 method were made repeatedly before and after the operations. After bilateral denervation in 9 rabbits, slight elevations of pressure were observed in 5.