Table 4.

Desensitization kinetics of outside-out patches (1 mM ACh)

A. Time constants (τ, in ms) and fractional amplitudes (a)
	Open	Shut
	τo	τ1	a1	τ2	a2	τ3	a3	τ4	a4	τ5	a4	nev
	8.19	0.77	0.19	5.30	0.29	40.3	0.24	534	0.20	2082	0.08	2577
	12.8	0.69	0.17	5.55	0.18	22.4	0.26	131	0.20	669	0.19	5349
	6.70	0.70	0.25	8.11	0.43	56.5	0.14	439	0.11	4643	0.07	2185
	12.6	1.39	0.12	6.47	0.28	35.1	0.22	201	0.20	938	0.18	3185
Mean	10.1	0.89	0.18	6.35	0.30	38.6	0.22	326	0.18	2083	0.13	3324
s.e.m.	1.5	0.17	0.03	0.64	0.03	7.1	0.03	96	0.02	907	0.03	705

B. Modelling results Linear model
	k01	k10	k12	k21	k23	k32	k34	k43	k45	k54*	N	k54
	133.0	386	742	225	117	30.6	13.7	3.3	0.3	0.6	275	0.0023
	90.0	580	1426	326	256	128.0	40.9	12.2	3.2	2.8	625	0.0045
	172.0	568	821	193	51	12.9	8.5	3.1	0.9	0.4	165	0.0023
	87.4	259	746	278	115	32.3	16.3	8.0	1.8	2.0	333	0.0059
Mean	120	448	934	256	135	51	20	6.7	1.5	—	—	0.0037
s.e.m.	20	77	165	29	43	26	7	2.1	0.6	—	—	0.0001

Star model
	k01	k10	k02	k20	k03	k30	k04	k40	k05	k50*	k01
	33.3	1312	37.8	190.6	29.6	25.0	23.4	1.89	9.2	0.48	0.0018
	19.6	1453	15.2	181.0	20.7	44.8	15.3	7.64	14.3	1.50	0.0024
	54.9	1450	66.4	125.4	21.0	17.8	15.7	2.29	10.0	0.22	0.0013
	12.1	722.9	23.5	155.6	17.2	28.6	15.8	4.99	13.9	1.07	0.0032
Mean	30.0	1234	35.7	163.1	22.1	29.1	17.6	4.20	11.8	—	0.0028
s.e.m.	9.4	174	11.2	14.6	2.6	5.7	1.9	1.34	1.3	—	0.0004

A, all patches required one open and five shut components; nev is the number of open + closed intervals in the record. B, the linear and star models are shown in Fig. 12; rate constants are given in s⁻¹.

^*The slowest recovery rate constant is predicted to scale linearly with the number of channels in the patch. The estimated number of channels (N) was determined from the ratio of the peak and single-channel currents for the patch (see Fig. 10C). The recovery rate constant (k₅₄) pertains to a single AChR.