FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-63/32

Title and Subtitle: Mechanism of autoregulation in the intact kidney

Report Date: December 1963

Authors: Hinshaw LB, Emerson TE, Brake CM

Abstract: The mechanism of renal autoregulation is unclear. The subject of the present investigation is the mechanism of autoregulation of blood flow in the intact kidney. The left kidney of the anesthetized dog was exposed via a flank approach. Renal venous outflow was measured during control periods and following separate elevations of renal artery pressure, renal vein pressure, and ureteral pressure.

Extravascular pressure (tissue pressure) was estimated by obtaining values of

1. deep vein pressure;
2. needle pressure;
3. and
4. large vein pressure and ureteral pressure elevations resulting in significant decreases in renal blood flow.

Results are in agreement with previously reported studies regarding the important role of extravascular pressure in autoregulation. Increases in renal artery pressure result in elevation of extravascular pressure which [compresses] the renal vasculature. Increases in renal vein and ureteral pressures do not decrease renal blood flow until approximating or exceeding resting tissue pressure. Results from carotid artery occlusion experiments indicate that extrarenal humoral influences may be superimposed in the autoregulatory phenomenon.

Key Words: kidney, renal autoregulation, extravascular pressure.

No. of Pages: 14