First responders arrive at a disaster scene—a bombing, say—and, after stabilizing victims, treat them with a puff of a nasal spray to prevent post-traumatic stress disorder (PTSD). The spray sends neuropeptide Y (NPY), a tiny but powerful signaling protein, deep into the nose and up into the brain. There it prevents the brain's stress system from kicking into overdrive and causing PTSD, which disrupts sleep, mood and thought in some people following trauma. The idea for this futuristic prophylactic treatment comes from recent studies in rats by neuroscientist Esther Louise Sabban of New York Medical College.

Sabban and her colleagues dosed rats with a nasal spray containing either NPY or saline and then exposed them to a one-time series of traumatic stresses, such as being immobilized and later forced to swim in a Plexiglas tube. Seven days later the researchers tested whether the rats exhibited anxious and depressionlike behaviors. Saline-treated rats did, but “the rats that received NPY looked very similar to the unstressed controls,” Sabban says. Likewise, the researchers found that stress hormones and receptors rose in the saline-treated but not the NPY-treated rats. Rats blasted with NPY immediately after the stressful experience were also protected, according to the study published in 2013 in Neuroscience.

A squirt of NPY into the nose can travel widely throughout the brain—but not the body, where harmful side effects could damage the heart. Recently Sabban determined that the treatment seems to work by reducing the number of receptors for the stress hormone cortisol, particularly in the ventral hippocampus, a brain area where emotional memories are formed. Future work will test whether NPY also alleviates established PTSD-like symptoms in rats.