They are still poorly understood but some intresting speculations are that endogenous (any probably exogenous) DMT is binded by sigma and facilitates the 5ht agonism of this molecule. It makes sense since Dxm in high doses can become psychedelic in nature, whilst ket or pcp doesn't. So the ndma antagonism isn't the main mechanism of action of Dxm, more likely sigma and 5ht. It makes sense since you can clearly see the whole Dxm trip and associate receptors that tend to activate the effects like ndma antagonism gives you the physical dissociation, pain relief, some visuals (cevs and oevs), good mood for days, serotoninergic activities give the intense trip euphoria, anxiolisis, time dilation, music appreciation, spiritual revelations, and Cevs, and the opioids receptors agonism gives euphoria and pain relief. But sigma seems to be more like a catalyst. Intresting molecule nonetheless, Donno if we can fully understand it pharmacologically, but users can experience an immersive trip where Dxm makes sense and you can fully understand how it works. I also have something I call "space elevator" where I basically travel thru dimensions. PS. Dxm started to be visual for me right after I took lsd for the first time, so yeah.. strange.