Hypotensive effect of chronic intrarenal infusion of acetylcholine during angiotensin hypertension |
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Authors: | J P Montani T H Adair B S Nuwayhid A C Guyton |
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Institution: | Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505. |
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Abstract: | We examined the role of the pressure natriuresis phenomenon in long-term arterial pressure control. Uninephrectomized dogs were housed in metabolic cages and made hypertensive with a continuous background intravenous infusion of angiotensin II (AngII, 12 ng/kg/min). To increase the ability of the kidney to excrete salt and water, we infused acetylcholine (ACH, 2.0 micrograms/kg/min), a potent natriuretic agen, directly into the renal artery. In four dogs, ACH decreased mean arterial pressure (MAP) from 144 +/- 5 mm Hg to 113 +/- 3 mm Hg. Sodium excretion increased by about 60% on the first day of infusion and then returned rapidly toward the control value. On cessation of the ACH infusion, there was a transient but marked sodium retention, and the hypertension returned. A control infusion of ACH intravenously rather than into the renal artery in the same four dogs did not affect MAP or sodium excretion during AngII hypertension. |
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