This study compares [¹¹C]flumazenil binding to GABA-A receptors in rats after a single injection of etifoxine versus the prototypical benzodiazepine, diazepam, which were both injected at doses reaching pharmacologically active concentrations in the brain.

A single dose of diazepam produced a significant decrease in the [¹¹C]flumazenil binding, which can be interpreted as benzodiazepine GABA-A receptor occupancy.

A single injection of etifoxine increased the [¹¹C]flumazenil binding, which can be interpreted as an allosteric effect on GABA-A receptors.

This PET protocol is transferable to human subjects for clinical pharmacology studies.