Cl- channels in basolateral TAL membranes. XIV Cl- channels in basolateral TAL membranes. XIV. Kinetic properties of a basolateral MTAL Cl- channel  Christopher J. Winters, W. Brian Reeves, Thomas E. Andreoli  Kidney International  Volume 55, Issue 4, Pages 1444-1449 (April 1999) DOI: 10.1046/j.1523-1755.1999.00401.x Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 1 Current-voltage relations under three different symmetrical solutions with each fitted by a linear regression. The experiments at each Cl- concentration were paired, with 150mm Cl-, N = 9, r = 0.99; with 320mm Cl-, N = 35, r = 0.99; and with 600mm Cl-, N = 3, r = 0.99. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 2 Relationship between gCl (pS) and aqueous-phase Cl- concentrations in 67 bilayer experiments using basolaterally enriched outer medullary vesicles from mouse (•; N = 14) or rabbit (○; N = 53) kidney. Four of the experiments were paired, and the remainder were not; there were no significant differences between the paired and unpaired experiments. The data were fitted according to the standard Michaelis-Menten kinetic expression for the relationship between conductance and concentration13 with an R2 value of 0.986. (GmaxCl = 114pS; K1/2 = 163mm. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 3 Relationship between log gCl (pS) and log [Cl-] using the data from Figure 2 at aqueous Cl- concentrations in the range 100 to 320mM, that is, at Cl- concentrations below saturation. Each symbol is for an individual channel in an individual bilayer from (•) mouse or (○) rabbit vesicles. Y = 0.91X -0.34; R = 0.922. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 4 I-V relationships for five different paired experiments with either 200mM KCl (▪) or 200mM KCl plus 150mM KI () in cis solutions. The trans solutions contained 50mm KCl. The solid curve represents a Goldman-Hodgkin-Katz equation fit of the cis 200mm KCl data using a Cl-:K+ ratio of 10:1. For 200mm KCl plus 150mm KI in cis solutions, the dashed line was drawn by eye. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 5 A representative tracing in a single Cl- channel illustrating, in a paired experiment, the effect of cis KI addition on a single channel current tracing at two different holding voltages, VH = 20mV and VH = 60mV. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions

Figure 6 Relationship between holding voltage and either τo (A, msec), the average time interval a channel remained open during a particular opening, or Po (B), the open time probability. The cis solutions contained either 200mm KCl (▪; N = 12, paired) or 200mm KCl plus 150mm KI (; N = 5, paired). The trans solutions contained 50mm KCl. Under paired control conditions without I-, Po was 0.09 ± 0.05 at 0mV and 0.56 ± 0.05 at 60mV (P = 0.0008). With I- addition to cis solutions, the paired Po values were 0.20 ± 0.09 at 0mV and 0.40 ± 0.08 at 60mV (P = 0.05). The unpaired P values with and without cis I- addition were 0.34 (NS) at 0mV and 0.07 at 60mV, respectively. Under paired control conditions without I-, τo (msec) was 4.1 ± 1.2 at 0mV and 13.1 ± 1.4 at 60mV (P = 0.00002). With I- addition to cis solutions, the paired τo values were 5.5 ± 1.4 at 0mV and 6.4 ± 1.3 at 60mV (P = NS). The unpaired P values with and without I- addition were 0.67 (NS) and 0.006 at 0mV and 60mV, respectively. Kidney International 1999 55, 1444-1449DOI: (10.1046/j.1523-1755.1999.00401.x) Copyright © 1999 International Society of Nephrology Terms and Conditions