Role of intrarenal venous pressure in the regulation of renal vascular resistance.

Abstract

A series of eighteen experiments have been carried out on the heart-lung perfused dog kidney, and the results have defined the role of the intrarenal veins in the autoregulation phenomenon. It was found that there are a variety of intrarenal venous pressures which differ greatly according to (a) anatomical location and (b) the prevailing renal-artery pressure. Findings have pointed out the importance of correct techniques in establishing the changes occurring in the intrarenal venous segment in response to an increase in renal artery pressure. An increase in ureteral pressure results in a significant decrease in renal blood flow and an increase in overall renal vascular resistance, which further supports the role of extra-vascular pressure increases in renal-flow regulation. The findings of the present study corroborate previous reports from this laboratory indicating that autoregulation is primarily accounted for on the basis of changes in renal extravascular pressure. Evidence has been provided for the absence of the "myogenie reflex" as a causal factor in autoregulation.