TABLE 1.

Variation of the WT ClC-0 current activated by protocol 2

		Before β-ME		After β-ME
Frog	No. of Oocytes	No. of crossover (mean ± SD)	I (μA) (mean ± SD)	No. of crossover (mean ± SD)	I (μA) (mean ± SD)
1	25	2.3 ± 1.0	11.7 ± 7.6	3.1 ± 0.8*	13.0 ± 8.9
2	7	3.4 ± 0.5	20.7 ± 5.3	3.4 ± 0.5	23.3 ± 7.2
3	10	2.9 ± 1.1	8.5 ± 4.4	3.4 ± 0.5	10.4 ± 4.2
4	12	3.2 ± 0.4	17.7 ± 6.7	3.3 ± 0.5	20.1 ± 6.9
5	9	3.2 ± 0.4	11.6 ± 4.1	3.2 ± 0.4	14.6 ± 4.2
6†	16	2.0 ± 1.3	14.0 ± 4.7	2.8 ± 0.8*	19.2 ± 6.1*
7†	16	1.9 ± 1.0	7.6 ± 3.8	3.1 ± 0.8*	14.9 ± 5.5*
8	17	3.4 ± 0.6	14.8 ± 3.6	2.8 ± 0.7	21.1 ± 4.7*
9	22	3.6 ± 0.6	9.4 ± 3.0	N.D.	N.D.
10	24	3.1 ± 0.5	11.7 ± 3.8	N.D.	N.D.
11†	14	0.1 ± 0.3	2.5 ± 1.1	2.9 ± 0.9*	10.6 ± 2.8*
12†	15	0.3 ± 0.5	1.7 ± 0.7	3.5 ± 1.1*	3.9 ± 1.5*
13†	4	0.3 ± 0.5	7.5 ± 4.3	2.3 ± 1.0*	9.4 ± 4.3*
14†	20	3.1 ± 0.6	8.4 ± 3.4	3.4 ± 0.7	11.9 ± 3.7*

Test voltages were from +60 or +80 mV to −160 mV in −20-mV steps. The same oocyte was recorded before and after a 1-h treatment with 5 mM β-ME. The number of trace crossovers and the current from the most depolarized voltage are shown. Frogs 1–7 were operated for the first time, whereas frogs 8–14 had received at least one surgery before the oocytes were harvested.

^*A statistical difference (pair t-test, p < 0.01) from the control value obtained before β-ME treatment, suggesting that the oocytes might be at least partially oxidized.

^†Frogs that had been kept longer than 3 months before oocytes were harvested.