TABLE 2

EC50 and maximum ΔF/F0 values (95% confidence interval in the parenthesis) for NAS and related compounds and benzodiazepines to increase FMP-Red-Dye flourescence in cells expressing α1β3γ2 and α4β3δ GABAAR in the absence of GABA

Dose-response curves were fit by nonlinear regression with a four-parameter logistic equation. Statistical differences among EC50 and maximum ΔF/F0 values were assessed independently by one-way analysis of variance with post hoc pairwise comparisons using Tukey’s honest significant difference test. On α1β3γ2 GABAARs, eltanolone with an IC50 value of 8 nM and maximum of 0.17 is the most potent and efficacious compound. Although on α4β3δ GABAARs, eltanolone with an IC50 value of 6 nM is the most potent compound, and XJ-42 with a maximum of 0.41 is the most efficacious compound. Each data point represents the mean (with 95% confidence interval in parenthesis) of measurements in 10 wells. *P < 0.001 when comparing IC50 values or maximum of compounds within each receptor isoform.

Compound Common Name (Systematic Name)α1β3γ2 (95% CI)α4β3δ (95% CI )
EC50Maximum ΔF/F0EC50Maximum ΔF/F0
Allopregnanolone (3α-hydroxy-5α-pregnan-20-one)9 nM * (7–11 nM)0.13 (0.12–0.13)27 nM (18–42 nM)0.16 (0.15–0.17)
Ganaxolone (3α-hydroxy-3β-methyl-5α-pregnan-20-one)24 nM (18–32 nM)0.14 (0.13–0.14)40 nM (21–73 nM)0.17 (0.15–0.18)
Eltanolone (3α-hydroxy-5β-pregnan-20-one)8 nM * (5–14 nM)0.17 * (0.16–0.18)6 nM * (2.4–16 nM)0.14 (0.12–0.15)
XJ-42 (3α,5α,20E)-3-hydroxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile)11 nM * (7–17 nM)0.13 (0.12–0.14)74 nM (47–116 nM)0.41 * (0.38–0.45)
5β,3α-THDOC (5β-pregnan-3α,21-diol-20-one)16 nM (6–45 nM)0.09 (0.08–0.10)54 nM (12–230 nM)0.09 (0.06–0.12)
Alphadolone 21-acetate (5α-pregnan-3α,21-diol-11, 20-dione 21-acetate)60 nM (33–100 nM)0.08 (0.07–0.09)700 nM (381–1220 nM)0.14 (0.1–0.18)
Alphaxalone ((3α,5α)-3-hydroxypregnane-11,20-dione)26 nM (13–54 nM)0.11 (0.10–0.11)83 nM (72–97 nM)0.13 (0.11–0.15)
Androsterone (5α-androstan-3α-ol-17-one)300 nM (200–551 nM)0.16 * (0.14–0.18)>1 µM
Etiocholanolone (5β-androstan-3α-ol-17-one)>1 µM>5 µM
Org 20599 ((2β,3α,5α)-21-chloro-3-hydroxy-2-(4-morpholinyl)pregnan-20-one)>1 µM>1 µM
UCI-50027 (3-[3α-hydroxy-3β-methyl-5α-androstan-17β-yl]-5(hydroxymethyl)isoxazole)>5 µM>5 µM
Progesterone (pregn-4-ene-3,20-dione)>5 µM>5 µM
Epiandrosterone (5α-androstan-3β-ol-17-one)>5 µM>5 µM
Indiplon (N-​​methyl-​​N-​​[3-​​[3-​​(2-​​thienylcarbonyl)​pyrazolo[1,​​5-​​α]​pyrimidin-​​7-​​yl]​phenyl]​-​acetamide)>5 µM>5 µM
Androstenediol (5-Androsten-3β, 17β-diol)>5 µM>5 µM
Dehydroepiandrosterone (DHEA) acetate>5 µM>10 µM
Dehydroepiandrosterone (DHEA)>5 µMInactive
20α-Dihydropregnenolone (5-pregnen-3β,20α-diol)>10 µM>10 µM
Ursodeoxycholic acid (sodium salt) (3,​7-​dihydroxy-​cholan-​24-​oic acid,​ monosodium salt)InactiveInactive
Cortisol (4-pregnen-11β,17,21-triol-3,20-dione)InactiveInactive
Diazepam (7-chloro-1-methyl-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one)>10 µM>10 µM
Midazolam (8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine)>10 µM>10 µM
Zolpidem (N,N,6-trimethyl-2-(4-methylphenyl)-imidazo[1,2-a]pyridine-3-acetamide)>10 µM>10 µM
  • CI, confidence interval.