Effect of Pulse Pressure and Mean Arterial Pressure Modification on Renal Hemodynamics and Electrolyte and Water Excretion

Studies were conducted to evaluate the influence of pulsatile versus nonpulsatile arterial perfusion pressure on plasma flow, filtration rate, sodium excretion, and urine volume. Through a wide range of mean renal arterial pressures, reduction of pulse pressure was without effect on renal function. The level of the mean arterial pressure, however, had a very dominant role in the electrolyte and water handling, decreases and increases in excretion paralleling the direction of change of the mean pressure. These alterations were observed even though filtration rate and plasma flow exhibited a marked degree of autonomy in the face of these pressure variations. Mechanisms by which these modifications in salt and water excretion could result from alteration in the mean arterial pressure are discussed.