Electrophysiological techniques were used to determine the electrical properties of the collecting duct (CD) cell in the isolated cortical collecting duct from obstructed (UUO(OK)) and contralateral (UUO(CK)) kidneys in rabbits 24 h after unilateral ureteral obstruction (UUO); results were compared with those from sham-operated kidneys. The lumen-negative transepithelial voltage and the basolateral membrane voltage (V(B)) were decreased in the UUO(OK), and increased in the UUO(CK). The transepithelial conductance (G(T)) was decreased in parallel with an increase in the fractional apical membrane resistance (fR(A)) and a decrease in apical membrane conductance in the UUO(OK). By contrast, the G(T) was increased in parallel with increases in apical and basolateral membrane conductances in the UUO(CK). The amiloride-sensitive changes in apical membrane voltage (V(A)), G(T) and fR(A) were lower in the UUO(OK), but greater in the UUO(CK). The changes in V(A) and G(T) upon raising the perfusate K+ concentration and upon addition of luminal Ba2+ were decreased in the UUO(OK), and increased in the UUO(CK). Addition of ouabain to the bath resulted in a smaller depolarization of V(B) in the UUO(OK), but in a greater depolarization in the UUO(CK). Upon lowering bath Cl-, the change in basolateral membrane electromotive force (DELTAEMF) was increased in the UUO(OK), and decreased in the UUO(CK). Reversely, upon raising bath K+, the DELTAEMF was decreased in the UUO(OK), and increased in the UUO(CK). We conclude: (a) the conductances of Na+ and K+ in the apical membrane, and active Na+-K+ pump activity and relative K+ conductance in the basolateral membrane are decreased in the UUO(OK), and increased in the UUO(CK); (b) the relative basolateral membrane Cl- conductance was increased in the UUO(OK), and decreased in the UUO(CK).
