Apical Na+ conductance in maturing rabbit principal cell

摘要: Net Na+ absorption in microperfused rabbit cortical collecting ducts (CCDs) is low during the 1st wk of postnatal life, increasing substantially thereafter [L. M. Satlin. Am. J. Physiol. 266 (Renal Fluid Electrolyte 35): F57-F65, 1994]. To establish whether rate observed immediately after birth due to a apical permeability neonatal principal cell, we used patch-clamp technique split-open CCDs isolated from maturing rabbits estimate conductance, number (N), and open probability (Po) channels cells. With LiCl pipette NaCl or potassium gluconate solution, warmed 37 degrees C, bath, inward currents with conductance approximately 11 pS (n = 23) were 17% cell-attached patches at 1 wk, 41% 2 43% 5 wk. The mean N per patch (0.22 +/- 0.09; n 36) was significantly less than that 2nd (1.38 0.39; 34) 5th (1.24 0.37; 21) life. Po, studied positive voltages, lower (0.085 0.035; 5) (0.345 0.063; 9) (0.291 0.058; 4). confirm 11-pS channel represented amiloride-sensitive channel, 2-wk-old 0.5 microM amiloride added solution. Amiloride led > 90% reductions closed times consistent blockade channel. These data indicate Po cells increase birth.