Many drugs—whether legal or illegal—act on one of the most abundant and important neurotransmitter receptors in the brain: type A GABA receptor (GABAA receptor). Particularly well-known are benzodiazepines, which are used for anesthesia during surgery and for the treatment of epilepsy, anxiety, and insomnia. The resolution of the three-dimensional structure of this receptor may one day lead to the development of better ways to treat these diseases.   The GABAA…