Direct assessment of tubuloglomerular feedback responsiveness in connexin 40-deficient mice.

Direct assessment of tubuloglomerular feedback responsiveness in connexin 40-deficient mice. Am J Physiol Renal Physiol. 2013 Feb 27; Authors: Oppermann M, Carota I, Schiessl I, Eisner C, Castrop H, Schnermann JB Abstract Participation of connexin40 (Cx40) in the regulation of renin secretion and in the tubuloglomerular feedback (TGF) component of renal autoregulation suggest that gap junctional coupling through Cx40 contributes to the function of the juxtaglomerular apparatus. In the present experiments we determined the effect of targeted Cx40 deletion in C57Bl/6 and FVB mice on TGF responsiveness. In C57Bl/6 mice, stop flow pressure (PSF) fell from 40.3 ± 2 to 34.5 ± 2 mm Hg in WT and from 31 ± 1.06 to 26.6 ± 0.98 mm Hg in Cx40-/-. PSF changes of 5.85 ± 0.67 Hg in wild type and of 4.3 ± 0.55 mm Hg in Cx40-/- mice were not significantly different (p=0.08). In FVB mice, PSF fell from 36.5 ± 1.8 mm Hg to 30.9 ± 1.75 mm Hg in WT and from 28.1 ± 1.6 to 25.4 ± 1.7 mm Hg in Cx40-/- with mean TGF responses being significantly greater in WT than Cx40-/- (5.5 ± 0.55 mm Hg vs. 2.7 ± 0.84 mm Hg; p=0.002). In both genetic backgrounds PSF values were significantly lower in Cx40-/- than WT mice at all flow rates. Arterial blood pressure in the animals prepared for micropuncture was not different between WT and Cx40-/- mice. We conclude that the TGF response magnitude in superficial cortical nephrons is reduced by 30-50% in mice without Cx40, b...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research