[GoldenRacer]

I don't think replacing oxygen in the brain is the main mechanism of action (in medical settings they mix nitrous and oxygen and it's still effective without risking hypoxia). Looking at Wikipedia it says the mechanism of action isn't fully understood but it says the effects "are likely caused mainly via inhibition of NMDA receptor-mediated currents".

I've been under the impression that biggest risk of long term use of nitrous is that it causes b12 deficiency which is really bad for your nervous system. Wikipedia also mentions that NMDA receptor antagonist in general are neurotoxic and studies in mice suggest that nitrous has this neurotoxicity.

[centizen]

It absolutely does, and with the recent uptick in recreational nitrous use we have clear examples of what it does to people. This is just one of the handful of cases of nitrous overuse leading to long term mobility loss

https://www.bbc.com/news/uk-england-london-67355097

[GoldenRacer]

I'm not sure I understand what you're saying. That article appears to be about a women who is now in a wheel chair due to nerve damage caused by a b12 deficiency which supports my comment that one of the most concerning risks of nitrous use is b12 deficiency.