Characteristics: Colorless, odorless noble gas with eight stable isotopes
Source: Extracted from air
Lights up: Used in lights, lasers, medical imaging agents
Lights out: Blocks glutamate receptors to produce anesthesia
Forbidden: Boosts erythropoietin and O2 capacity, banned by World Anti-Doping Agency
Pencil in one more possible use for the element xenon: In addition to being an anesthetic and medical imaging agent, the noble gas could become a treatment for posttraumatic stress disorder (PTSD). Among its biological effects, xenon blocks glutamate receptors involved in reconsolidation—a process in which a reactivated old memory gets packed away by the brain as if it were new. That got neuroscientist Edward G. Meloni of McLean Hospital, in Belmont, Mass., thinking that xenon might help PTSD patients, who reexperience painful memories when reminded of past traumas. Meloni teamed with Harvard Medical School researchers to test the hypothesis in rats. The team shocked the rats’ feet after playing a tone, conditioning the animals to freeze in fear upon hearing the tone days later. When the researchers played the tone and then immediately exposed rats to a puff of xenon—below the amount it would take to anesthetize them—the rats’ fear responses were reduced for up to two weeks (PLOS One 2014, DOI: 10.1371/journal.pone.0106189). Current PTSD treatments rarely fix underlying problems, so xenon may prove helpful if future research can demonstrate that the treatment won’t disrupt beneficial memories, says Christopher K. Cain, who studies PTSD at New York University.