Table 2

Mean ED₅₀ values and 95% CLs for the flumazenil discrimination dose-effect curve under control conditions and after pretreatment with positive GABA_A modulators

Drug/Dose	Flumazenil Discrimination
Drug/Dose	ED₅₀	95% CL
	mg/kg
Control	0.03	0.01–0.06
Benzodiazepine site
⁺ Flunitrazepam
0.32 mg/kg	0.09^2-a	0.04–0.15
1.0 mg/kg	0.21^2-a	0.03–0.51
⁺ Abecarnil
3.2 mg/kg	0.08^2-a	0.03–0.15
5.6 mg/kg	N.A.	N.A.
Neuroactive steroid site
⁺ Androsterone
10.0 mg/kg	0.07^2-a	0.02–0.11
32.0 mg/kg	0.33^2-a	0.09–0.69
⁺ Dihydroandrosterone
32.0 mg/kg	0.12^2-a	0.02–0.23
56.0 mg/kg	0.30^2-a	0.10–0.58
⁺ Epipregnanolone
32.0 mg/kg	0.07^2-a	0.05–0.09
56.0 mg/kg	0.09^2-a	0.03–0.16

Data are from at least three monkeys.

N.A., not applicable; only one monkey responded ≥80% on the flumazenil lever.
↵2-a Significantly different from control (p < 0.05).