Table 1. Summary of deactivation time constants and MK-801 block time constant.

Deactivation time constants and time constants for MK-801 block were obtained by fitting current traces using double exponential and single exponential functions, respectively. For estimation of open probability (Po), 1 μM (+)-MK-801 was used to block currents activated by 100 μM glycine plus 1 mM glutamate at pH 8.0. MK-801 block rates (1/τ) for all receptors were divided by the block rate of diheteromeric GluN1/2A receptors (A/A) to obtain the scaling factors and Po was calculated by multiplying the previously determined Po of GluN1/2A receptors at pH 8.0 (Yuan et al., 2009) by the scaling factor determined for each receptor. Data are shown as mean ± SEM. n.d: not determined.

Group	τfast (ms)	τslow (ms)	τfast %	τweighted (ms)	n	MK-801 (1 μM) block τ (ms)	Estimated Po	n
A/A	31 ± 1	111 ± 14	92 ± 2	36 ± 1	6	92 ± 4	0.48	6
A/B	39 ± 3	139 ± 15	85 ± 3	50 ± 3	18	107 ± 3	0.41	6
B/B	174 ± 12	586 ± 35	60 ± 4	333 ± 17	8	292 ± 20	0.15	6
Acc/A	44 ± 4	171 ± 9	77 ± 3	73 ± 5	5	n.d
Bcc/A	43 ± 3	246 ± 40	86 ± 4	71 ± 8	9	n.d
Bcc/B	224 ± 27	1079 ± 58	46 ± 3	680 ± 26	9	n.d
Acc/B	119 ± 13	470 ± 51	59 ± 6	248 ± 10	10	n.d
Abcc/B	138 ± 12	434 ± 54	61 ± 8	246 ± 11	7	n.d
Bacc/B	91 ± 2	310 ± 29	55 ± 7	188 ± 18	5	n.d
A/Ab	38 ± 2	134 ± 23	89 ± 3	49 ± 3	6	137 ± 10	0.32	3
Ab/Ab	55 ± 7	178 ± 21	78 ± 6	80 ± 8	6	187 ± 8	0.24	6
Ba/B	58 ± 9	192 ± 37	68 ± 11	89 ± 8	6	116 ± 6	0.38	4
Ba/Ba	50 ± 4	160 ± 25	67 ± 8	81 ± 9	7	111 ± 5	0.40	3
Ba/A	30 ± 2	87 ± 7	89 ± 4	36 ± 3	4	113 ± 13	0.39	4
Ab/B	109 ± 4	434 ± 57	81 ± 3	166 ± 7	6	209 ± 21	0.21	5