Sleeping drug action. Artwork showing the action of various sleeping drugs on a nerve cell. The cell membrane (pink) is shown, along with associated proteins (orange). Sleeping drugs work by mimicking the action of a natural molecule called gamma-aminobutyric acid (GABA, red spheres). When GABA molecules reach a nerve cell they bind with specific receptor molecules, triggering the opening of chloride channels (at centre left). Chloride ions (large green spheres) are then able to pass through, making the nerve cell less excitable and promoting sleep. Sleeping drugs like benzodiazepines (small green spheres) trigger the same mechanism.