Table 1.

Summary of activation properties.

Agonist	Background agonist	L	K (μM)	c
GABA	None	9000	35.3 ± 6.6	0.0045 ± 0.0004
Propofol	None	9000	44.8 ± 8.9	0.04 ± 0.002
Alfaxalone	2 μM GABA	66 ± 36	2.9 ± 0.5	0.11 ± 0.006
Diazepam	2 μM GABA	37 ± 16	0.17 ± 0.02	0.18 ± 0.004

The K (equilibrium dissociation constant of the closed receptor) and c (ratio of the equilibrium dissociation constant of the closed receptor to that of the open receptor) values were estimated by fitting Equation (1) to the concentration-response data (Fig. 5). The number of binding sites was held at 2 for GABA, 3 for propofol, 2 for alfaxalone, and 1 for diazepam (see Methods). The value for L was held at 9000 in the absence of a background agonist or at the value calculated from estimated open probability of the background agonist (2 μM GABA) as (1 − P_o,background)/P_o,background.