g-Aminobutyric acid type A (GABA A) receptors, ligand-gated ion channel receptors for the inhibitory neurotransmitter GABA, mediate neuronal inhibition in the CNS, including the spinal cord. Based on their subunit compositions (more specifically the a subunit isoform included in the pentameric receptor complex), they can be subdivided into six major subtypes (from a1 to a6). GABA A receptors containing a1, a2, a3, or a5 subunits are sensitive to modulation by classical benzodiazepines, whereas those containing a4 or a6 subunits instead of a1, a2, a3, or a5 subunits are insensitive. The compound PF-06372865, the subject of a study by Nickolls and colleagues 1 in a recent issue of the British Journal of Anaesthesia, was developed by Pfizer Inc (Cambridge, UK) as a partial