Table 3.

Single channel properties of the de novo GABRB mutations associated with infantile spasms.

	α1β3γ2L (n)		α1β1γ2L (n)
	wt β3 (6)	β3(N110D) (5)	wt β1(6)	β1(F246S) (3)
Channel conductance (pS)	24.79 ± 1.62	23.66 ± 0.97	25.72 ± 1.09	22.15 ± 0.75*
Mean open time (ms)	6.60 ± 0.73	7.00 ± 0.36	4.30 ± 0.78	16.13 ± 0.14***
Opening frequency (S−1)	49 ± 2	48 ± 4	30 ± 3	14 ± 1**
Open probability (Po)	0.62 ± 0.05	0.11 ±0.03****	0.48 ±0.03	0.55 ±0.02
Open time constants:
τo1 (ms)	3.18 ± 0.28	3.98 ± 0.44	2.39 ± 0.14	4.49 ± 0.05***
τo2 (ms)	9.77 ± 0.84	8.92 ± 1.17	8.33 ±1.01	16.6 ± 0.3**
τo3 (ms)	20.8 ± 3.4	21.6 ± 5.1	17.4 ± 5.3	47.9 ± 3.5**
ao1 (%)	67 ± 1	66 ± 8	72 ± 6	19 ± 3***
ao2 (%)	28 ± 2	29 ± 8	25 ± 5	75 ± 4***
ao3 (%)	5 ± 2	5 ± 1	6 ± 2	6 ± 1
Burst duration (ms)	20.13 ± 0.72	14.34 ± 1.17**	13.33 ± 2.38	42.95 ± 2.61**
Openings/burst	3.12 ± 0.19	2.21 ± 0.16*	2.42 ± 0.11	2.49 ± 0.13
Burst time constants:
τ1(ms)	2.54 ± 0.20	4.85 ± 0.60*	2.42 ± 0.24	5.62 ± 1.04*
τ2(ms)	35.4 ± 2.9	24.6 ± 3.4*	21.2 ± 3.1	52.0 ± 1.6***
a1 (%)	37 ± 6	55 ± 3*	54 ± 3	20 ± 3***
a2 (%)	63 ± 6	45 ± 3*	49 ± 2	80 ± 3***

Values represent mean ± S.E.M.

^{*, **, *** and ****}indicate p < 0.05, p < 0.01, p<0.001 and p < 0.0001 (unpaired t-test) statistically different from wt, respectively.