Fig. 1.
A: time control experiments. Left: increasing the perfusion rates in the late proximal tubule 2 consecutive times decreased stop-flow pressure (PSF) in a reproducible manner (○, first curve; ●, second curve). Right: maximum PSF responses in the first and second curves. B: effect of inhibiting tubuloglomerular feedback (TGF) with Na-K-2Cl cotransporter (NKCC2) blocker furosemide (furo) on PSF. Left: increasing the perfusion rates in the late proximal tubule decreased PSF (○, vehicle). This response was completely blocked when the NKCC2 inhibitor furosemide was added to the perfusate (●, furosemide). Right: maximum PSF responses in the vehicle and furosemide curves. ***P < 0.001.