University of Pennsylvania Apr 3 2025 Nitrous oxide-better known as "laughing gas"-can potentially transform treatment for tough-to-beat depression. This centuries-old anesthetic gas targeted specific brain cells in mice and quickly reduced symptoms, according to new research from the Perelman School of Medicine at the University of Pennsylvania, reported today in Nature Communications . Nitrous oxide is the oldest anesthetic we've got-it's been used worldwide for over 180 years, costs about $