People have used atypical antipsychotics for years to abort bad trips (especially effective is Seroquel because it also has a sedatory effect). It definitely works, but most people would take an oral form which is not immediate (30-60 minutes depending on the drug). Presumably an injection would be immediate or almost immediate.

Science is so funny sometimes. You could probably have a successful career by reading erowid and "discovering" things about drugs.

Erowid or PiHKAL :)

Maybe machine learning techniques could correlate chemical drug composition with experiences described on erowid and similar databases to provide new insights into brain chemistry? It would presumably take some effort to automate distinguishing important data (exact substance, dosage taken, emotions, physical reactions, euphoria, paranoia...) from random hallucinatory tails.

It should be "the [..] receptor-antagonist ketanserin" (can't take a dose of a receptor). And the effect isn't complete if I understand it correctly. But higher doses or a more potent antagonist could block the psychedelic effects completely, yes.

I'm not quite sure if LSD has non-psychedelic effects that are mediated through other mechanisms (such as other serotonin receptors, or maybe the dopaminergic system). From what I seem to remember (from that neurology lecture, mind you (where I was high)), LSD has some cardiovascular effects – basically everything you may experience from a large dose of caffein: rapid heartbeat, sweating, nervousness.

LSD has a very wide receptor binding profile, see Table 8 of this paper: http://www.maps.org/research-archive/w3pb/2008/2008_Passie_2...

It also does bind to dopamine receptors, which is why it's more stimulating than other psychedelics.

It's also worth looking into the "research chemical" 25I-NBOMe[1] -- it's "a highly potent full agonist for the human 5-HT2A receptor" and has similar effects to LSD. It could be a useful tool in further understanding the role of this specific receptor in the human brain. Perhaps its effects could be seen as a subset of LSD's?

1: https://en.wikipedia.org/wiki/25I-NBOMe

I think that's more or less the idea, and I also think the article accidentally a word- I imagine that should say selective serotonin 2A receptor antagonist ketanserin. Trazodone is said to do this too.

Ketanserin was only administered 60 min before the LSD. This study did not test for subjective effects with order of brain uptake for either drug.