Table 2.

Effects of iodine oxidation and DTT reduction on normalized WT, I229C, A288C, I229C/A288C, I229C/A288C/C290S, and I229C + A288C GlyRs currents

GlyRα1	Gly	Gly (post-oxidation)	Gly (post-reduction)	n
Cross-linking (I2) and reduction in the absence of glycine
WT	0.95 ± 0.05	0.83 ± 0.15	1.14 ± 0.28	8
I229C	0.87 ± 0.04	1.01 ± 0.08	1.15 ± 0.16	6
A288C	1.20 ± 0.07	1.18 ± 0.10	0.98 ± 0.13	7
I229C/A288C	0.97 ± 0.09	0.91 ± 0.23	1.00 ± 0.38	7
Cross-linking (I2) and reduction in maximal glycine
WT	0.97 ± 0.08	0.93 ± 0.10	0.99 ± 0.14	6
I229C	0.96 ± 0.09	1.34 ± 0.25	0.90 ± 0.21	5
A288C	0.96 ± 0.09	0.85 ± 0.28	1.02 ± 0.38	5
I229C/A288C	0.98 ± 0.09	0.36 ± 0.03**	0.67 ± 0.11*	5
I229C/A228C/C290S	1.02 ± 0.07	0.31 ± 0.10**	0.49 ± 0.16**	6
I229C + A288C (1:1)	1.08 ± 0.07	0.98 ± 0.12	1.17 ± 0.25	6

^*p < 0.05 and

^**p < 0.01 significantly different from initial glycine response for each receptor by one-way ANOVA and the Dunnett’s post-test. Two applications of maximal glycine were followed by oxidation with iodine (0.5 mmol/L, 1 min), maximal glycine, reduction with DTT (10 mmol/L, 3 min), and a final application of maximal glycine. Washout times were 15 min intervals between applications. Application of iodine and DTT were carried out in either the presence or absence of glycine. Cross-linking with iodine in the presence of glycine resulted in decreased receptor responses in only the I229C/A288C and I229C/A288C/C290S receptors. The glycine responses for each receptor type were normalized to the respective initial glycine response (1.00, not shown), and the data were averaged. Data are expressed as the mean ± SEM. DTT, dithiothreitol; GlyR, glycine receptor; WT, wild-type.