DOI keeps popping up in 5-HT2A receptor mapping papers, anyone tracking the research angle?

Question

Been reading a few newer papers that use DOI as the standard 5-HT2A tool because it sticks around so long, and honestly the receptor mapping stuff is way more interesting to me than the psychedelic effect itself. The half-life and duration make it useful for imaging and longitudinal studies, which is probably why labs keep reaching for it over shorter acting agonists. What caught my eye is how DOI is being used to figure out which 5-HT2A sub-populations do what, and whether downstream signalling differences explain why some psychedelics feel anti-neuroinflammatory versus purely hallucinogenic. That could actually matter for the mood and longevity crowd, not just trippy therapy people. It is still very much a lab tool though, and I would not extrapolate from rodent DOI data to "this is how a clinical psychedelic will behave" because the receptor landscape is not identical. Is anyone here actually following the 5-HT2A signalling research closely, and do you think this kind of work will eventually change how psilocybin and LSD trials are designed, or is it mostly basic science that won't move the needle for users? 😅

fasted_scientist · Accepted Answer

DOI is a bit of a weird one because its long half-life is both the reason it's useful in the lab and exactly why nobody touches it for actual human therapeutic work. The receptor mapping angle is proper interesting though, the idea that 5-HT2A isn't just one homogenous population and that downstream signalling beta-arrestin vs G-protein pathways and that whole biased agonism debate might explain why some compounds feel anti-inflammatory rather than purely hallucinogenic. Ngl I reckon this is one of those areas where the rodent data looks tidier than the reality. Mouse 5-HT2A distribution isn't a perfect mirror of ours, and DOI's duration creates its own confound because downstream signalling gets weird over long receptor occupancy. For trial design though, yeah I think it'll matter eventually. If you can map which receptor sub-populations drive which effects, you could theoretically design compounds that skip the trip but keep the plasticity or anti-neuroinflammatory bits. Whether that

jared_j · Answer

Yeah the biased agonism thing is what hooked me too, fwiw. Feels like the field is finally moving past "hallucinogen or not" as the binary and asking what each compound actually does downstream. The rodent caveat is fair though, I keep reminding myself that mouse receptor distribution isn't a 1:1 map for us.

elle_z · Answer

Biased agonism is exactly the right word for it, glad someone else is tracking that angle. The downstream signalling split is what got me digging into this stuff in the first place because it might explain why some compounds seem to nudge neuroinflammation markers in rodents without the full hallucinogenic load, which would matter a lot for the longevity people. Are you following the 5-HT2A mGluR2 heteromer stuff at all? That paper from a few months back suggesting receptor population and pairing changes the downstream read keeps nagging at me, and I can't tell if it's a real finding the field is taking seriously or just a cool result that got overhyped.

elle_z · Answer

Haha yes exactly, that's my whole point lah. The biased agonism thing is what got me hooked too, like if different 5-HT2A subpopulations really do route to beta-arrestin vs G-protein differently then the "anti-neuroinflammatory without the trip" idea isn't pure sci-fi, it's at least mechanistically plausible on paper. But you're right that mouse receptor distribution being tidier than reality is a real caveat. Were you thinking of specific papers where the rodent to human translation broke down, or more just the general receptor expression differences?

DOI keeps popping up in 5-HT2A receptor mapping papers, anyone tracking the research angle?

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