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Psilocybin and neurogenesis

Talisman

Bluelighter
Joined
Nov 17, 2004
Messages
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Recent research has shown that 5-HT-1A agonists stimulate neurogenesis[1]. This study only mentions d-fenfluramine and 8-hydroxy-2-dipropylaminotetralin. Is anyone familiar with research regarding psilocybin (or other tryptamines) and brain cell formation?



[1] Regulation of Adult Neurogenesis by Psychotropic Drugs and Stress
http://jpet.aspetjournals.org/cgi/content/full/299/2/401#SEC4
 
Hmmmm.... I'm pretty sure there is no published research looking at that. If someone was interested about the effect of 5-HT1A receptor activation, they'd have to be pretty crazy to use a psychoactive tryptamine... meanwhile, 5-HT1A receptor blockade only reduced neurogenisis by 30%... so there's obviously other factors in there.

But still, interesting.
 
Why are you interested in neurogenesis? I study it in my lab and I also study the 5HT1A receptor.
 
It seems he's questioning whether tryptamines stimulate neurogenesis.
 
meowmix said:
Why are you interested in neurogenesis? I study it in my lab and I also study the 5HT1A receptor.

I am rather interested in the topic of neurogenesis in general. I'm intrigued by findings such as
  • Rat neurogenesis (in the dentate gyrus) was found in one study to be proportional to the distance (willingly) run by the rat.
  • Alcohol inhibits it.
  • One suggested explanation for the mechanism for SSRIs is that they potentiate neurogenesis, which might explain the several- week delay between consumption and effects.

In particular, I'm impressed by the studies that have shown significant improvement in behavioral activities (e.g., maze navigation) correlated highly with increased neurogenesis.

I would be curious to know if psilocybin might have similar effects (fighting depression, increasing intelligence, etc.). It's perhaps a long shot, but maybe interesting to investigate.
 
^^^
It has been hypothesised that neurogenesis is the real reason SSRIs alleviate depression...... I forget where I read that though...
 
^^^ Yeah, I should have been more clear by saying:

"One suggested explanation for the mechanism for SSRIs in alleviating depression is that they potentiate neurogenesis"
 
Interesting-

What you are asking is what a whole shitload of people in the field are asking. Nobody really knows. Did you read this paper by Hen?

Requirement of hippocampal neurogenesis for the behavioral effects of antidepressants.
Science. 2003 Aug 8;301(5634):805-9.


Very interesting but do you really think neurogenesis is responsible for the effects of antidepressants? Antidepressants typically have a lag time of about 3 or 4 weeks. This fact has been used to support the idea that neurogenesis must occur for the effect- it takes time for these new cells to be born and incorporated into the network.

The problem is does this extremely tiny number of cells really make a difference? Think about the already established network of brain cells that are present. Do the small number of cells born in the dentate really have that much of an impact on mental health? Is the stimulation of neurogenesis simply a side effect of SSRI treatment?

MDMA also causes increased neurogenesis but I don't think that many people would argue that it will alleviate depression. If you feed MDMA to mice you can see the loss of cells and projections in the area around the dentate. The hypothesis is that the loss causes stimulation of neurogenesis- but does this make us more happy?

It is an extremely complicated question- many activities and substances have been linked to increases or decreases in neurogenesis. I, along with too many others, will be hacking away at this problem for the next 4 years while trying to earn my PhD.

Um, also, I went to the Society for Neuroscience meeting and saw some interesting work about forced exercise compared to volunatry in terms of stimulating neurogenesis. The presenter did not have all studies complete but I could find her name if you are interested in looking out for publications in the future.

Why the interest? Do you work in this field or in a related field? Just curious.
 
I don't buy the neurogenisis/antidepressant thing at all...
5-HT1A agonists aren't antidepressant for one, yet they (should) stimulant neurogenisis. There are antidepressant treatments which don't stimulant neurogenisis.

That 'exercise produces neurogenisis, and exercise is antidepressant' argument, I think it stinks... if they can bust out some BDNF antisense oligonucliotides or a trkB receptor antagonist, that will sort that one you....

But I'm just cynical...
 
A lot of leading neuroscientists in psychiatry and related fields were not happy that the paper discussed above was accepted to Science, and as a Research Article on top of that.

Particularly offensive was the lack of any behavioral data from paradigms that model depression, as opposed to anxiety. I mean, forced swim (dropping a rodent into a chamber with deep water and timing how long they will struggle before giving up) is one of the stupidest, easiest behavioral paradigms. Whether or not it actually models depression is another question, but it is used to test potential antidepressants and the mechanisms of established ones. The absence of any data from even that depression model makes me wonder…

I'm with Bilz0r on this one; it's all speculation at best, and complete bullshit at worst.
 
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