Table 3.

Rate constants for transitions between states of α1β3γ2, α4β3γ2 and α4β3δ GABA_A receptors activated by GABA, muscimol and THIP

		α1β3γ2			α4β3γ2			α4β3δ
Constant	Unit	GABA	Muscimol	THIP	GABA	Muscimol	THIP	GABA	Muscimol	THIP
k1	m−1* s−1	51 × 106	453 × 106	1.6 × 106	3.5 × 106	7.1 × 106	3.9 × 106	32 × 106	15 × 106	5.7 × 106
k−1	s−1	399	245	3	6	6	6	7	1.3	56
k2	m−1* s−1	28 × 106	186 × 106	2.6 × 106	3.2 × 106	5.9 × 106	0.8 × 106	47 × 106	21 × 106	0.15 × 106
k−2	s−1	360	428	842	51	28	285	12	7	53
δ	s−1	219	217	110	2	5	6	6	6	7
δ−1	s−1	17	21	15	3	11	15	3	6	2
β1	s−1	570	427	40	57	45	39	20	22	142
α1	s−1	2268	2471	2695	2972	2887	1625	465	1324	956
β2	s−1	2556	2690	1543	936	887	676	255	325	1362
α2	s−1	356	324	394	970	1023	812	1500	1729	348
K1	μm	7.9	0.5	1.7	1.8	0.8	1.5	0.2	0.1	9.8
K2	μm	12.8	2.3	330	16.0	4.7	357	0.3	0.3	359
D		13	10	7	0.62	0.45	0.40	2.0	1.0	3.5
E1		0.25	0.17	0.01	0.019	0.016	0.024	0.04	0.02	0.15
E2		7.2	8.3	3.9	1.0	0.9	0.8	0.17	0.19	3.9

The rate constants were determined by optimally fitting the single channel data for each receptor (α1β3γ2, α4β3γ2 and α4β3δ) in the presence of each agonist (GABA, muscimol and THIP) at each of the three concentrations with the linear/branched receptor model using QuB. Values are accrued from n= 13–20 patches.