Water and electrolyte transport in Henle's loop and distal tubule after renal sympathectomy in the rat.

The effect of acute renal denervation (AD) on transtubular movement of water and electrolytes in Henle's loop (LH) and distal tubule (DT) of superficial nephrons was studied by the technique of in vivo microperfusion in Inactin-anesthetized hydropenic male rats. In time-control experiments (n = 6) no changes in either whole kidney or single nephron function were detected. Predenervation results of denervation experiments (n = 10) were similar to those of the time-control series. AD resulted in increased urine, sodium, and potassium excretion in the absence of changes of either arterial blood pressure or GFR. Compared with predenervation data, AD led to significant decreases in net transtubular fluxes (J) of water and sodium in both perfused segments with delivery kept constant (delta JNa: LH = 144 +/- 26 peq X min-1, 9.1 +/- 0.3%; DT = 94 +/- 11 peq X min-1, 22.3 +/- 1.1%). Potassium absorption in the loop decreased but an increase in net addition (secretion) of K in the distal tubule on denervation occurred (delta JK = 8.7 +/- 1.9 peq X min-1, 68.7 +/- 3.2%). Use of the reperfusion technique gave similar results. These results indicate that efferent renal sympathetic nerve activity directly influences water, sodium, and potassium transport in the loop of Henle and distal tubule of the anesthetized rat.