Table 2.

Comparison of Boltzmann fit parameters before and after changing ion composition in pore

(a) 100K solution supplemented with 10 mM CsCl 
 ALEXA-488 (11) MTS-TAMRA (6) 
100K 100K+Cs 100K 100K+Cs 
Ftotalmax 1.00 ± 0.01 1.20 ± 0.03 1.00 ± 0.03 1.30 ± 0.04 
V0.5F (mV) −67.8 ± 1.1 −72.2 ± 1.6 −49.7 ± 3.4 −58.2 ± 2.9 
zF 1.09 ± 0.05 1.27 ± 0.08 0.77 ± 0.06 0.96 ± 0.08 
(b) Reducing external K+ from 100 mM (100K solution) to 2 mM (100Na solution) 
 ALEXA-488 (5) MTS-TAMRA (4) 
100K 100Na 100K 100Na 
Ftotalmax 1.00 ± 0.01 1.10 ± 0.02 0.99 ± 0.06 1.30 ± 0.09 
V0.5F (mV) −67.8 ± 0.8 −68.1 ± 1.1 −62.6 ± 5.5 −69.7 ± 6.1 
zF 1.08 ± 0.04 1.44 ± 0.08 0.81 ± 0.09 0.90 ± 0.12 
(c) Analysis of fast component of ALEXA-488 fluorescence after supplementing with 10 mM CsCl or external K+ reduction. 
 ALEXA-488 (9) ALEXA-488 (5) 
100K 100K+Cs 100K 100Na 
Ffastmax 0.62 ± 0.04 0.66 ± 0.03 0.58 ± 0.04 0.61 ± 0.04 
V0.5F (mV) −90.2 ± 4.5 −88.5 ± 3.3 −80.5 ± 4.6 −81.5 ± 4.4 
zF 0.82 ± 0.10 0.89 ± 0.09 0.83 ± 0.12 1.02 ± 0.2 
(a) 100K solution supplemented with 10 mM CsCl 
 ALEXA-488 (11) MTS-TAMRA (6) 
100K 100K+Cs 100K 100K+Cs 
Ftotalmax 1.00 ± 0.01 1.20 ± 0.03 1.00 ± 0.03 1.30 ± 0.04 
V0.5F (mV) −67.8 ± 1.1 −72.2 ± 1.6 −49.7 ± 3.4 −58.2 ± 2.9 
zF 1.09 ± 0.05 1.27 ± 0.08 0.77 ± 0.06 0.96 ± 0.08 
(b) Reducing external K+ from 100 mM (100K solution) to 2 mM (100Na solution) 
 ALEXA-488 (5) MTS-TAMRA (4) 
100K 100Na 100K 100Na 
Ftotalmax 1.00 ± 0.01 1.10 ± 0.02 0.99 ± 0.06 1.30 ± 0.09 
V0.5F (mV) −67.8 ± 0.8 −68.1 ± 1.1 −62.6 ± 5.5 −69.7 ± 6.1 
zF 1.08 ± 0.04 1.44 ± 0.08 0.81 ± 0.09 0.90 ± 0.12 
(c) Analysis of fast component of ALEXA-488 fluorescence after supplementing with 10 mM CsCl or external K+ reduction. 
 ALEXA-488 (9) ALEXA-488 (5) 
100K 100K+Cs 100K 100Na 
Ffastmax 0.62 ± 0.04 0.66 ± 0.03 0.58 ± 0.04 0.61 ± 0.04 
V0.5F (mV) −90.2 ± 4.5 −88.5 ± 3.3 −80.5 ± 4.6 −81.5 ± 4.4 
zF 0.82 ± 0.10 0.89 ± 0.09 0.83 ± 0.12 1.02 ± 0.2 

Values are shown as mean ± SE as reported by fit to pooled, normalized data using the Boltzmann equation. Data for individual cells were normalized to the control condition (100K) before pooling. Number of cells analyzed are given in parentheses. Boltzmann fit to ∆Ffast, normalized to Ftotalmax. Shaded values after changing to 100K+Cs solution or 100Na solution as indicated. For ALEXA-488 labeling in c, there was no significant difference between the fit parameters of ∆Ffast, compared with the control (100K) (t test, P > 0.05) with either Cs supplement or 100K/100Na substitution.

or Create an Account

Close Modal
Close Modal