Nitric oxide mediates anomalous tubuloglomerular feedback in rats fed high NaCl diet after subtotal nephrectomy.

Nitric oxide mediates anomalous tubuloglomerular feedback in rats fed high NaCl diet after subtotal nephrectomy. Am J Physiol Renal Physiol. 2018 Oct 31;: Authors: Thomson SC Abstract Tubuloglomerular feedback (TGF) responses become anomalous in rats fed high NaCl diet after subtotal nephrectomy (STN) such that stimulating TGF causes single nephron GFR (SNGFR) to increase rather than decrease. Micropuncture experiments were performed to determine whether this anomaly results from heightened nitric oxide response to distal delivery, which is a known mechanism for resetting TGF, or from connecting tubule TGF (cTGF), which is a novel amiloride-inhibitable system for offsetting TGF responses. Micropuncture was done in Wistar Froemter rats fed high NaCl diet (HS) for 8-10 days after STN or sham nephrectomy. TGF was manipulated by orthograde microperfusion of Henle's loop with artificial tubular fluid with or without NOS inhibitor, LNMMA, or the cell-impermeant amiloride analog, benzamil. SNGFR was measured by inulin clearance in tubular fluid collections from the late proximal tubule. TGF responses were quantified as the increase in SNGFR that occurred when the perfusion rate was reduced from 50 to 8 nl/min in STN or 40 to 8 nl/min in shams. The baseline TGF response was anomalous in STN HS (-4±3 vs 14±3 nl/min, P<0.001). TGF response was normalized by perfusing STN nephron with LNMMA (14±3 nl/min, p<0.005 for ANOVA cross...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research