TABLE 3

Relative affinities of GABA_AR PAMs for intersubunit anesthetic sites in the presence of GABA

Data from Tables 1 and 2 are summarized by identifying the site with highest affinity (H), the sites binding with 2- to 10-fold lower affinity (I), or >15-fold lower affinity (L) than the high-affinity site. For the drugs that, in the presence of GABA, bind nonequivalently to the β⁻ sites, prediction of the high-affinity β⁻ site is based upon [³H]R-mTFD-MPAB photolabeling in the presence of bicuculline (see Results and Discussion).

Ligands	β⁺ Interfaces	β⁻ Interfaces
	β⁺–α⁻ IC₅₀	α⁺–β⁻ IC₅₀	γ⁺–β⁻ IC₅₀
	μM	μM	μM
That distinguish the two β⁻ sites
4-benzoyl-propofol	L 100	L 330	H 0.5
Loreclezole	I 9	H 1	L 300
TG-41	H 0.02	I 0.1	L > 100
Tracazolate	H 8	L > 300	I 18
That do not distinguish the two β⁻ sites
Etomidate	H 2.0	L 430	L 430
Propofol	H 7.8	I 44	I 44
4-Cl-propofol	H 4.9	I 20	I 20
4-acetyl-propofol	H 48	H 32	H 32
4-(tert-butyl)-propofol	I 130	H 17	H 17
4-benzyl-propofol	I 30	H 6	H 6
Stiripentol	I 130	H 60	H 60
4-OHPheMe-propofol	L 160	H 10	H 10
R-mTFD-MPAB	L 32	H 0.7	H 0.7