The production of arterial hypertension by chronic renal artery-nerve stimulation.

Since reducing the blood flow to the kidneys by mechanical constriction of the renal arteries produces hypertension (2, 4, 6, 14), it seemed desirable to ascertain whether decreasing renal blood flow by sfimulation of renal vasocon-strictor nerves might likewise cause an elevation in blood pressure. It is known (3, 7, 10, 15) that active renal vasoconstriction occurs in response to stimulation of the nerves to the kidney. However, under the conditions used in prior experiments the response has been of short duration, presumably because of rapid fatigue. Cressman and Blalock (1939) attempted without success to produce hyper-tension in dogs by chronic stimulation of the splanchnic nerves with an alternating current of 60 cycles per second. increase in blood pressure in only one of three dogs stimulated. They were able to obtain a transient A clue to the reasons for their failure to obtain hypertension appears to be supplied by the work of Maltesos and Schneider (1938-39). These investigators reported that stimulation of autonomic constrictor nerve fibers with sinusoidal currents of ten cycles per second or less caused vasoconstriction without fatigue in contrast to the rapid fatigue which occurred when higher frequencies were used. Therefore it seemed desirable to study the effects of various types of electrical stimulation of the renal nerves over short and long periods of time on renal blood flow and arterial blood pressure. Since both the artery wall and its associated nerve fibers are stimulated by the method described below, the effects will be referred to as those of renal artery-nerve stimulation. METHODS. Medium sized mongrel dogs of either sex were used as the experimental animals. Shielded electrodes of no. 18 fine silver wire molded in lucite were slipped over both renal arteries and their accompanying nerves. An obturator molded of plastic closed the slot in the electrode block so that the artery and its associated nerves were enclosed within a smooth tube. The lead wires were silver wire cables made from 24 strands of no. 36 fine silver wire insulated with spectacle tubing. The resistance of the electrodes when in place was 800 to 2000 ohms. In the acute experiments various types of current were used as stimuli. Alternating sine wave currents varying from one to three thousand cycles per second were tested. and interrupted direct currents of constant voltage were also tested. Condenser discharges at frequencies of one to seventy per second In the chronic …