Table IV.

Single Channel Properties of Wild-type and Mutant Na⁺ Channels

		WT		F1489Y		F1489I		F1489A		F1489Q		T1491M
−40 mV
open times
τ1, (ms) (A)		0.32 ± 0.04		0.45 ± 0.06		0.39 ± 0.06		0.46 ± 0.21 (0.51)		1.50 ± 0.24		—
τ2, (ms) (A)		—		—		—		1.59 ± 0.00 (0.49)		—		—
No. of events		1,469		3,074		3,388		5,417		3,875		—
closed times
τ1, (A)		—		0.21 ± 0.06 (0.41)		0.42 ± 0.23 (0.33)		0.25 ± 0.04 (0.53)		0.28 ± 0.07 (0.34)		—
τ2, (A)		—		1.33 ± 3.18 (0.27)		7.80 ± 0.00 (0.67)		3.44 ± 0.66 (0.48)		2.08 ± 0.79 (0.66)		—
τ3, (A)		—		17.08 ± 2.75 (0.32)		—		—		—		—
No. of events		—		1,826		1,044		3,783		3,420		—
−20 mV
open times
τ1, (ms)		0.39 ± 0.04		0.58 ± 0.10		0.46 ± 0.06		0.58 ± 0.00 (0.33)		2.12 ± 0.15		0.57 ± 0.00 (0.40)
τ2, (ms) (A)		—		—		—		2.00 ± 0.65 (0.67)		—		1.45 ± 1.70 (0.60)
No. of events		2,427		5,173		7,141		6,930		15,350		8,934
closed times
τ1, (A)				0.21 ± 0.06 (0.31)		0.37 ± 0.13 (0.23)		0.27 ± 0.06 (0.32)		1.38 ± 0.49		0.13 ± 0.00 (0.38)
τ2, (A)				18.76 ± 0.00 (0.69)		7.76 ± 0.00 (0.77)		3.02 ± 0.00 (0.68)		—		12.89 ± 0.77 (0.62)
No. of events				2,404		2,832		7,849		13,567		2,517
0 mV
open times
τ1, (ms)		0.36 ± 0.04		0.51 ± 0.10		0.47 ± 0.07		0.56 ± 0.36 (0.42)		2.26 ± 0.20		1.40 ± 0.30
τ2, (ms)		—		—		—		1.92 ± 0.00 (0.58)		—		—
No. of events		1,123		1,373		5,334		5,603		8,669		3,239
closed times
τ1, (A)		—		0.08 ± 0.00 (0.28)		0.25 ± 0.07 (0.25)		0.07 ± 0.02 (0.29)		0.20 ± 0.05 (0.33)		0.12 ± 0.01 (0.50)
τ2, (A)		—		14.49 ± 0.71 (0.72)		5.54 ± 0.00 (0.75)		1.96 ± 0.37 (0.71)		1.46 ± 0.79 (0.67)		12.08 ± 0.79 (0.50)
No. of events		—		768		1,638		3,208		7,377		2,119

τ1, τ2, and τ3 (ms), time constants of exponential fits to open and closed time distributions. Open time distributions were constructed from patches containing one to two channels, and closed time distributions were constructed from patches containing one channel. A, relative amplitudes of individual fit components. The errors indicated are values for SD estimated by the fitting routine.