Table 2.

Effects of Cu-Phen on the amplitude and voltage dependence of WT KCNQ2 and S4 cysteine mutants

Channel	V50	V50-Cu-Phen	ICu-Phena
	mV	mV
WT Q2	−32.2 ± 1.4 (10)	−29.5 ± 1.1 (10)	1.07 ± 0.11 (10)
S195C Q2	5.2 ± 4.0b (8)	0.8 ± 6.0b (8)	0.26 ± 0.06b (8)
R198C Q2	−31.0 ± 4.4 (7)	−5.3 ± 4.8 (7)	0.27 ± 0.06b (7)
R201C Q2	—	—	0.33 ± 0.07b (7)

Xenopus oocytes were incubated for 2 min at −80 mV in ND96 solution in the absence or presence of 100 µM Cu-Phen, washed with ND96 for another 5 min at −80 mV, and then depolarized from −90 to 45 mV in 15-mV increments and repolarized at −60 mV. Conductance–voltage relations were constructed and data were fitted to a single Boltzmann function to yield the V₅₀ values. The values in parentheses correspond to the number of cells examined. Data are expressed as mean ± SEM.

^aThe change in current amplitude was expressed as a ratio I_Cu-Phen of the current measured in the same cell at 45 mV after and before Cu-Phen application at −80 mV.

^bStatistically different from the WT KCNQ2 value, calculated by two-tailed unpaired Student’s t test, assuming equal variances; P < 0.01.