Persistent hypertension in the dog following disruption of the carotid sinus nerves and subsequent unilateral renal artery constriction.

CONSTRICTION of one renal artery in the dog does not as a rule produce sustained hypertension. Removal of the contralateral kidney, or bilateral renal artery constriction is necessary for the production of permanent hypertension. On the other hand, sustained hypertension may be produced regularly in the rat by unilateral renal artery constriction. Tt has been postulated that, in the rat, long standing hypertension damages the contralateral kidney which then maintains the elevated pressure by continued renin production. Another explanation attributes the persistence of hypertension to an extra-renal mechanism, initiated by the transient effect of unilateral renal ischemia and becoming self-perpetuating as a result of participation of the extra-renal mechanism. Still others have suggested that disturbance of a depressor function of the normal kidney necessary to maintain blood pressure within normal limits is responsib'e for the sustained hypertension/' Experiments have shown that baroreceptors are set at the high level in chronic renal hypertension and, tlras, could participate in the maintenance of chronic hypertension.' In a previous paper we reported that disruption of the carotid sinus nerves and subsequent constriction of one renal artery in the dog resulted in persistent moderate hypertension in the majority of animals. We concluded that carotid sinus disruption probably enhanced the development of hypertension in the dog following unilateral renal artery con-