Influence of tissue pressure on renal blood flow autoregulation

Abstract

Experiments have been undertaken to determine the role which tissue pressure plays in renal blood flow autoregulation. The following results have been obtained: 1) During occlusion of the ureter of the dog undergoing mannitol diuresis renal blood flow changes little, or increases, while tissue and ureteral pressures may increase up to 70 and 100 mm Hg, respectively. 2) Rapid sustained increases in ureteral pressure are associated with a rapid initial decline in renal blood flow followed by a gradual return to or near the control value; during these blood flow changes the elevated needle and ureteral pressures are constant. 3) During ureteral occlusion vasodilator drugs have little effect on renal blood flow. 4) The decapsulated kidney autoregulates. These data indicate that renal blood flow autoregulation cannot be explained on the basis of the tissue pressure hypothesis, but rather give further support to the myogenic theory.