Quantification of Baroreceptor Influence on Arterial Pressure Changes Seen in Primary

SUMMARY We studied the role of the sino-aortic barorecep-tors in the gradual development of hypertension induced by prolonged administration of small amounts of angiolensin II (A II) in intact dogs and dogs with denervated sino-aortic barorecep-tors. Short-term 1-hour infusions of A II (1.0-100 ng/kg per min) showed that conscious denervated dogs had twice the pressor sensitivity of intact dogs. Long-term infusions of A II at 5.0 ng/kg per min (2-3 weeks) with continuous 24-hour recordings of arte-rial pressure showed that intact dogs required 28 hours to reach the same level of pressure attained by denervated dogs during the 1st hour of infusion. At the 28th hour the pressure in both groups was 70 % of the maximum value attained by the 7th day of infusion. Both intact and denervated dogs readied nearly the same plateau level of pressure, the magnitude being directly related both to the A II infusion rate and the daily sodium intake