Flumazenil-d5

Flumazenil-d₅ is intended for use as an internal standard for the quantification of flumazenil by GC- or LC-MS. Flumazenil is a GABA_A receptor antagonist (IC₅₀ = 2 nM in a radioligand binding assay using rat cortical synaptosomes).¹ Flumazenil also acts as a partial agonist of GABA_A receptors, decreasing the amplitude of electrically stimulated population spikes in rat hippocampal CA1 pyramidal neurons.² It increases the number of entries into the open arms of the elevated plus maze in high-anxiety BALB/c, but not C57BL/6, mice when administered at doses ranging from 0.1 to 1,000 µg/kg.³ Flumazenil (5 and 10 mg/kg) prevents a reduction in burying behavior induced by the GABA_A receptor positive allosteric modulator allopregnanolone in ovariectomized rats when administered at doses of 5 and 10 mg/kg.⁴ Formulations containing flumazenil have been used to reverse sedation induced by benzodiazepines and in the treatment of benzodiazepine overdose or withdrawal.