Inhibition of essential-like tremor in GABA_A receptor α1^–/– mice by ethanol and MK-801. (A) Ethanol (0.25–2.5 g/kg) inhibited the essential-like tremor (approximately 19 Hz) in α1^–/– mice in a dose-dependent manner with an ED₅₀ of 0.35 mg/kg reaching a maximal inhibition of 100% (n = 5–11 per genotype). Ethanol (0.25 g/kg) increased physiological tremor (approximately 32 Hz) in α1^+/+ mice but lacked any effect at higher doses. (B) MK-801 (0.01–0.2 mg/kg) reduced the approximately 19 Hz tremor power in α1^–/– mice with an ED50 of 0.024 mg/kg reaching a maximal inhibition of 65–80% (n = 5–6). *P < 0.05; **P < 0.01; ***P < 0.001.