Tissue pressure and autoregulation in the dextran-perfused kidney

¹ Departments of Physiology, Surgery, and Physiological Chemistry, University of Minnesota Medical School, Minneapolis, Minnesota

Experiments were performed on isolated dog kidneys alternately perfused with homologous blood and dextran. Renal artery pressure, tissue pressure, perfusate flow rate and vascular volume changes were measured as arterial pressures were progressively elevated. Marked increases in overall vascular resistance RA/F occurred in all dextran- and blood-perfused kidneys throughout the autoregulatory range. Results indicate that autoregulation of flow occurs in both blood- and dextran-perfused kidneys concurrent with increases in tissue pressure. Dextran- and blood-perfused kidneys show similar degrees of autoregulation when values are expressed in terms of increase in flow per unit rise of arterial pressure and compared to preautoregulation values.