it's a real fun idea, but in reality, we don't have receptors for psychedelics to begin with. they're just doing their own regular function related to normal brain behavior which just so happens to be for brain behavior related to sight or whatevs. what happens after that is usually through testing for something unrelated, it's discovered that a newly invented or discovered chemical just so happens to fit one or more of the existing receptor sites and affect us in an unusual way.