Table 3. Fitted parameters for Scheme 2... | Rockefeller University Press

Table 3.

Fitted parameters for Scheme 2 constrained by time constants acquired with nominally 0 Ca²⁺, and either 0 or 30 µM NS11021

Parameter	0 µM	30 µM: α β γ δ D	30 µM: γ δ	30 µM: α β	30 µM: D
α (s^-1)	1,162	3,387	1,162	4,833	1,162
β (s^-1)	31,020	17,200	31,020	11,230	31,020
γ (s^-1)	5,128	1,154	925.0	5,128	5,128
δ (s^-1)	1.40	1.45	2.23	1.40	1.40
z_α (e₀)	0.31	0.31	0.31	0.31	0.31
z_β (e₀)	−0.31	−0.31	−0.31	−0.31	−0.31
z_γ (e₀)	−0.025	−0.025	−0.025	−0.025	−0.025
z_δ (e₀)	0.29	0.29	0.29	0.29	0.29
D	8.2	5.2	8.2	8.2	25.6
χ²	13.4	14.9	82.5	167.4	209.7

Parameter	0 µM	30 µM: α β γ δ D	30 µM: γ δ	30 µM: α β	30 µM: D
α (s^-1)	1,162	3,387	1,162	4,833	1,162
β (s^-1)	31,020	17,200	31,020	11,230	31,020
γ (s^-1)	5,128	1,154	925.0	5,128	5,128
δ (s^-1)	1.40	1.45	2.23	1.40	1.40
z_α (e₀)	0.31	0.31	0.31	0.31	0.31
z_β (e₀)	−0.31	−0.31	−0.31	−0.31	−0.31
z_γ (e₀)	−0.025	−0.025	−0.025	−0.025	−0.025
z_δ (e₀)	0.29	0.29	0.29	0.29	0.29
D	8.2	5.2	8.2	8.2	25.6
χ²	13.4	14.9	82.5	167.4	209.7

Time constants of activation/deactivation over voltages ranging from −240 to 230 mV, with nominally 0 Ca²⁺ and 0 µM NS11021 used to estimate parameters for Scheme 2, as described in Materials and methods. These were used as a base set of parameters to describe the time constants in the presence of 30 µM NS11021, by adjusting parameters corresponding to J₀ (α, β), L₀ (γ, δ), or D. These adjusted values are shown in bold. Thus, adjusting γ and δ yielded the lowest χ² value among these three comparisons, although adjusting these parameters in combination yielded a statistically better fit. Time constants predicted by these parameters superimposed on experimental data are shown in Fig. 8. χ² based on 41 experimental data points each for 0 and 30 µM NS11021.

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