ELI5 Laughing Gas - why does N2O make us laugh?

What happens inside your brain when you inhale nitrous oxide? Why is it called laughing gas? When did we start using laughing gas for medical use cases? Is it safe? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: linguista420, slugcunt69, infinitysquared and kodack10 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]