Hallucinations and Visual Disturbances?

[nAON]

Excellent question! There is a good deal of evidence that increased glutamate activity is a downstream effect of 5-HT2A effects, and the visual effects of hallucinogens are one possible consequence. Glutamate nerve endings express 5-HT1B/1D heteroceptors that inhibit glutamate release. So potentially by releasing massive amounts of serotonin, MDA may somewhat "modulate" its actions at 5-HT2A.

Interesting that it's not a common feature of all SERT drugs though (at least not as distinctly as MDA). I wonder, if it has affinity in its own right, or perhaps is localises within the visual cortex at different levels? Gonna go on a search to see if there's any imaging data about 5HT2A distribution in the VC, will report back

 

[serotonin2A]

Interesting that it's not a common feature of all SERT drugs though (at least not as distinctly as MDA). I wonder, if it has affinity in its own right, or perhaps is localises within the visual cortex at different levels? Gonna go on a search to see if there's any imaging data about 5HT2A distribution in the VC, will report back

It is well known that there high levels of 5-HT2A in visual cortex of humans. You can check PET, autoradiography, etc. MDA binds to 5-HT2A and is an agonist. There was recently a clinical trial in humans that looked at visual effects:

http://www.ncbi.nlm.nih.gov/pubmed/21152030

 

[nAON]

I know that, I was just wondering if perhaps different effects of ligands could be attributed to them selectively distributing to higher or lower levels in the visual stream - thought I had was if your average psychedelic causing geometrics does so through fucking with lateral inhibition/excitation at lowlevel V1-V4, perhaps the more 'real' hallucination of MDA are mediated by 2A agonism in VMT/Perirhinal Cortex/other higher-level areas?

Will give that study a read today though, cheers for link^

 

[serotonin2A]

I know that, I was just wondering if perhaps different effects of ligands could be attributed to them selectively distributing to higher or lower levels in the visual stream - thought I had was if your average psychedelic causing geometrics does so through fucking with lateral inhibition/excitation at lowlevel V1-V4, perhaps the more 'real' hallucination of MDA are mediated by 2A agonism in VMT/Perirhinal Cortex/other higher-level areas?

Will give that study a read today though, cheers for link^

Most likely the simple and complex hallicinations are mediated in different locations, as you described (probably through effects on visual association cortices and up through the dorsal and ventral streams). I think that disyribution differences may explain some differences between hallucinogens but I don't think that is probably the case for MDA.