TABLE 1. Estimates of IC₅₀ values and Hill coefficients for resting, inactivated, and open states of Na⁺ channel isoforms.

Data were collected by pulse protocols described in Figs. 2, 6, and 9. Results were fitted with Hill equation; IC₅₀ values are shown with Hill coefficients listed in parenthesis. The resting and inactivated Na⁺ channel block were determined in wild-type isoforms, whereas the peak and open sustained block were determined in inactivation-deficient rNav1.4-WCW, hNav1.5-CW, and hNav1.7-WCW mutant Na⁺ channels. Open-channel block of sustained rNav1.4-WCW/F1579K Na⁺ currents displayed a significant increase in its IC₅₀ value compared with rNav1.4-WCW (P < 0.001). All data were derived from n = 5 except as indicated otherwise.

Channel State	Wild-Type Channels			Mutant Channels
	rNav1.4	HNav1.5	hNav1.7	rNav1.4-WCW	rNav1.4-WCW/F1579K	hNav1.5-CW	hNav1.7-WCW
	μM			μM
Resting	N.A.	N.A.	N.A.	225.4 ± 16.3 (0.92 ± 0.05)	N.A.	136.5 ± 196.2 (2.77 ± 12.15)	N.A.
Inactivated	75.0 ± 3.5 (1.41 ± 0.10)a	65.5 ± 9.4 (1.52 ± 0.32)	59.9 ± 3.8 (1.16 ± 0.09)
Open: Sustained				2.4 ± 0.2 (1.15 ± 0.09)	40.7 ± 1.3 (1.12 ± 0.04)	6.2 ± 0.7 (1.28 ± 0.17)	1.7 ± 0.1 (1.25 ± 0.08)

N.A., not applicable for direct measurements, since their estimated IC₅₀ values were >300 μM.

^an = 6.