“The recent discovery that the hippocampus is able to generate new neurons throughout a human’s lifespan has changed the way we think about the mechanisms of psychiatric disorders and drug addiction,” says Wen Jian and colleagues in a study published in the Journal of Clinical Investigation in 2005. It appears that cannabinoids are able to modulate pain, nausea, vomiting, epilepsy, ischemic stroke, cerebral trauma, multiple sclerosis, tumors, and many other disorders. Cannabinoids act on two types of receptors, the CB1 receptors (found mainly in the brain) and the CB2 receptors (found mainly in the immune system). The CB1 receptor is one of the most abundant G protein coupled receptors in the mammalian brain and it accounts for most, if not all, of the centrally mediated effects of cannabinoids. Cannabionoid receptors are evolutionarily conserved amoung various vertebrates and invertebrates which have been separate for 500 million years.
Hippocampal neurogenesis is suppressed following chronic administration of the major drugs of abuse (including opiates, alcohol, nicotine, and cocaine). However, CB1-knockout mice display significantly decreased hippocampal neurogenesis, suggesting that CB1 receptors activated by endogenous, plant-derived, or synthetic cannabinoids may promote hippocampal neurogenesis.
Wen Jiang and colleagues have given the first evidence suggesting that both embryonic and adult hippocampal neural stem/progenitor cells (NS/PCs) express CB1 receptors. Cannabinoids can regulate the proliferation of hippocampal NS/PCs by acting on CB1 receptors. They found that both the synthetic cannabinoid HU210 and the endocannabinoid anandamide profoundly promote embryonic hippocampal NS/PC proliferation.
Chronic, but not acute, HU210 significantly increases the number of newborn hippocampal neurons in adult rats by promoting NS/PC proliferation. These promoting effects are not the outcome of hippocampal neuronal death, as no neuronal loss or dying hippocampal neurons were detected following chronic HU210 injection. A significant increase was observed in the hipoppocampal newborn neurons of mice following twice-daily HU210 injection for 10 days.
It has been shown that acute, high doses of cannabinoids produce anxiety-like effects in rats and depression-like effects in mice. But chronic administration of high, but not low, doses of HU210 exerts anxiolytic- and antidepressant-like effects. This suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration. “This increase in hippocampal neurogenesis underlies the mechanism of anxiolytic- and andtidepressant-like effects produced by a high dose chronic HU210 treatment.”
Source: Jiang W, Zhang Y, Xiao L, Cleemput JV, Ji S-P, Bai G, & Zhang X (2005). Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects. Journal of Clinical Investigation, 115, 3104-3116
-Bryan Perkins
Science. Why not? 
June 20, 2009 at 11:20 am
popurls.com // popular today…
story has entered the popular today section on popurls.com…
June 20, 2009 at 2:07 pm
Reddit.
June 20, 2009 at 4:23 pm
Smokedit.
June 20, 2009 at 4:35 pm
I dont get what they’re talking about, but I did hit some cannabis today, is my brain better? 😀
June 20, 2009 at 5:43 pm
I don’t know if you can say better, but you could probably say larger. But only if the cannabis had a high THC content and you continue to use it over a long period of time. Because it is only high doses over a long period of time that produce this effect. Actually acute high doses have somewhat of an opposite effect. And chronic low doses are no good either.
Science. Why not?
June 20, 2009 at 10:51 pm
Wonderful Science, but only in conjunction with its proofs of The Largest Brain (Better dope than what we got, you say?) Yes! Who made who? Who made You?
June 22, 2009 at 9:31 pm
See how smart Pot makes you? lol Scroll down to Bill Hick’s video (Hey, thanks, Tommy, if it was you who put it here). He talks about the Master Brain, God, also – now I don’t feel like a religious nut completely. Hicks figures He smoked it too. Yes: “Great minds think Alike!” (Shut up, mother. Fools do so differ.)
June 23, 2009 at 9:38 am
The proofs of the Largest Brain?
June 20, 2009 at 4:36 pm
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June 20, 2009 at 4:49 pm
This is just one of 50,000 reasons why it should be legalized.
June 20, 2009 at 5:40 pm
I agree, and you can expect more articles on some of the other reasons in the future.
June 20, 2009 at 9:49 pm
I knew 25 years ago, when I first seriously smoked it: If I had enough for long enough I could beat my nicotine addiction once & for all.Never have the opportunity, that’s all.Yeah, get real. Gays can marry but we can’t somoke?I think they should marry if they want to.Also think they should be able to smoke if they want to & me too.
June 21, 2009 at 5:02 am
Great points. You’re still boring and unoriginal… Maybe that’s a side effect of hippocampal neurogenesis
June 21, 2009 at 1:37 pm
Smoke all u want. Just don’t stone and drive.
June 20, 2009 at 5:05 pm
Wow.
June 20, 2009 at 5:44 pm
Exactly.
June 20, 2009 at 7:22 pm
So we should smoke more and better weed more often?
June 20, 2009 at 8:01 pm
Absolutley!!!
June 20, 2009 at 10:09 pm
You are both correct.
June 20, 2009 at 10:48 pm
Yeah, you should if you want to be smart enough to fix everything else that is wrong with you, Ha. Ha! Love it!!!
June 21, 2009 at 11:39 am
Good Lord! I think I’ve got some serious catching up to do!!!
June 20, 2009 at 7:55 pm
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June 20, 2009 at 8:01 pm
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June 20, 2009 at 8:08 pm
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June 20, 2009 at 10:46 pm
Don’t you all think that maybe tobacco is good too, like everything is good in its time/place? Study said cannabis can cure the effect of tobacco but I think something’s screwy today.There were 3 things Dafoe had Crusoe take off the ship, 3 things vital to his survival: Rum, tobacco,gun powder: to the island.Rum for the parasites, tobacco for the parasites and blood cleaning.The Indians have taught us, again, the value of tobacco.A newly discovered rare plant in New Zealand that is paramount in treating HIV can only be produced in equitable amounts in the medium of Tobacco. Potatoes and corn, in that order, are the only other two it can be produced in, but not nearly as abundantly as in the tobacco leaf. These are the 3 things the North American Indians gave to the world, and definitely not by accident, the f’n bang, or any other illogical theory.
Continued on my blog.
June 21, 2009 at 5:07 am
shuuuuuuuuuuuuuuuuuuuuuut up
June 22, 2009 at 8:33 pm
Shut up yourself, Bertie or Smoke some more! Saturday nite, had a few,riginality was not my object, just a voice thinking how much I prefer the poison called Pot to almost anything offered by Pfizer, Bayer, Proctor & Gamble or any of the others who killed my mother & brother-in-law with “pharmaceuticals.” Both were poisoned & I for one, prefer my “poison” to theirs.Go away, Bertie.
August 30, 2009 at 10:17 am
How can you even compare cannabis to those shite medications?
June 21, 2009 at 12:21 am
I believe an ‘acute’ dose would be a large amount of strong herb. What does a ‘chronic’ dose mean though?
June 21, 2009 at 12:53 am
‘Chronic’ in this case means sustained at a reasonably consistent level, over a prolonged period of time.
June 21, 2009 at 9:23 am
Bingo.
June 21, 2009 at 1:22 am
But what about the other sideeffects,the lungs probably dont like thc more than it likes cigarettes.And do we really think that all of the users can get this drug,in the right dose,under a really long time,so they can get these positive effects on the brain.
Just some thoughts=)
Have a nice day!
June 21, 2009 at 9:40 am
I will be doing another article on the effects of thc and marijuana smoke on the lungs in the future. But I don’t think we would have to worry about people getting a high enough dose once they give it a try.
June 22, 2009 at 9:53 am
Last months CMAJ had an article on the effects of marijuana and tobacco smoke on the lungs- specifically COPD. The findings were that marijuana alone does not have the same detrimental effect that tobacco does. Though when consumed together, they effects are greater.
June 23, 2009 at 9:43 am
I am going to go look that up now. Thank you.
June 21, 2009 at 1:34 am
hey guys
we should legalise pot now
just saying
June 21, 2009 at 5:03 am
Woah! Dude! Sick!
June 22, 2009 at 6:52 pm
WE DONT WANT TO LEGALIZE!
June 22, 2009 at 6:55 pm
we want to DECRIMINALIZE!
there is a huge difference folks!
if we legalize it will be like cigs and alcohol they can regulate what days it can be bought sold etc. IF we decriminalize we keep ALL our rights.
Legalization of pot will create less quality end product to be bought and sold in stores.
If we decriminalize you can still grow your own a much happier solution.
June 22, 2009 at 8:56 pm
Yes, I worry about the quality too if it is legalized. It’s great if you can grown your own but we don’t ever evenget seeds anymore, where I am. And we hear from time to time that “something else” has been added to the pot which is a scary thought.If it was legalized chances are just as good that it would be tampered with – think melamine in dog food, phalates in babies milk – you’ve got the picture. Decriminalize it, Yes!
June 24, 2009 at 1:37 am
There is no reason to believe that quality would diminish with legalization. On the contrary, consider the state of things in the Netherlands. Second, even if it were heavily taxed, the price would fall dramatically if there were no of risk of jail for distribution (remember decriminalization applies to possession, not selling). Lastly what would be added to it that you are so worried about? Or are you just that paranoid?
June 24, 2009 at 1:10 pm
I think I agree with you on this one Michael. I don’t see any reason the quality would go down. And although there will be taxes added on, the raw price will go down by making it legal.
June 21, 2009 at 2:28 am
This is pretty neat (and a well-written summary) but I wouldn’t use it as a rationalization to smoke more pot than you otherwise would. At the risk of offending some of my friends, all brain sciences are in their infancy, and I guarantee that all of this will seem very quaint in a couple generations, much like ‘balancing the humors’ for medicine, or trying to turn lead into gold for chemistry. I would vote to legalize pot, but I wouldn’t advise anyone to smoke it based on one study finding increased hippocampal neurogenesis in embryonic (and most likely albino) lab rats.
June 21, 2009 at 9:24 am
Reasonable.
June 21, 2009 at 4:29 am
This is very interesting, and very risky! My take is, we do what we absolutely must,
I dont know if it is useful to try rationalizing it, here the assumption made is that “hippocampal neurogenesis” can actually improve life quality or expectancy in any way
June 21, 2009 at 9:26 am
I am not necessarily trying to say it will make your life better. But it does make our current drug laws seem a bit hypocritical. Chronic high doses of alcohol destroy brain cells. Chronic high doses of cannabinoids promote the formation of new brain cells. Why is one legal and the other not?
June 22, 2009 at 9:10 pm
No one ever said the powers that be had to have any brains, did they? I understand they drink a lot, generally. “They” being our politician & lawmakers. (Always thought they were trying to drown their guilty consciences & to top it off it makes them even stupider.) Many years ago studies revealed that the Orientals, Chinese in particular, had concaves on their brains that were not found in Occidentals. The assumption was that it occured because of the marijuana and/or opium they smoked in great quantities and the findings intimated that they were far more intelligent, as a result.
June 23, 2009 at 9:40 am
What studies? What are you talking about here? You seem to be making a lot of sweeping generalizations.
June 23, 2009 at 5:01 pm
Somewhere in the CBC (Canadian Broadcast Corporation) Radio archives there is at least one story about the concaves found on the brains of Orientals (only) but it was as long ago as perhaps 25 years & I do not have the time nor know if I would even be allowed access to these records. Reuters, if you have access, likely carried the story first. You, with your science background, should have a better idea of how to confirm what I wrote of. You might have to leave the internet and go up into the moldy old halls of Academia, even! Anthropologist or geneticists at maybe NYU (you might contact Todd Disotel) would have the info. available on these particular studies. It was a long time ago and all I remember is what I wrote. As far as sweeping generalities, I’m not sure what you refer to really, except the studies mentioned they had only found these on brains belonging to Orientals. Perhaps they identified a certain province in China, perhaps it was in Siberia. I do know the oldest cache of marijuana to date, was found in Xinjiang Province, beside the 4000 year old mummified corpses of what is believed to be Caucasians (some even had blonde hair)! Another twist….What that does to the concave theory, I don’t know. And, oh, don’t want to get me started on the proofs of a Master Brain/Computer/God at all! Thanks Brian. Interesting topics.
June 23, 2009 at 5:09 pm
I am most interested in your ‘proofs’ of a ‘Master Brain/Computer/God’. If you actually have some I would be most grateful to hear about them.
June 21, 2009 at 5:17 am
thank you so much ….nice post dear …i think i find one nice blog on wordpress ….keep it up …from ashvin
June 22, 2009 at 9:11 pm
I’ll smoke to that!
June 23, 2009 at 9:13 am
Thank you both.
June 21, 2009 at 5:54 am
This is not another reason why drugs should be legalized, a government controlled drug should be created and administered in supervised conditions and limits to how much is taken. Drugs have screwed up millions of lives this should not be allowed to screw several million more.
June 21, 2009 at 9:29 am
But why is alcohol legal when it causes more damage to the brain than cannabinoids? The arbitrariness with which we choose what is legal or not is a reason why they should be legal. Or we could go the other way and make alcohol and tobacco illegal. But that would be dumb and is never going to happen. And wouldn’t drugs screw up less lives if they were legal? At least people would have the opportunity to use the responsibly. When drugs are illegal the only way to use them is to abuse them.
June 21, 2009 at 11:48 am
I agree with you. Have seen alcohol do a lot more damage than pot. Both behaviorally and physically. Make pot legal. Tax it even. Hopefully then those tax dollars would please, please, please be spent on something far more meaningful than clogging up the jails and court systems with pot users. Utterly senseless.
June 22, 2009 at 9:41 pm
Couldn’t agree more. Most people who can’t handle their alcohol and get violent find they are able to control their behaviour very well if they stick strictly to pot. Mixing the two is a terrible combination for some with the results being as terrible or worse for those who can’t drink (for whatever reason – many are allergic to the molds and/or yeasts and the brain stone combo is devastating). Many should stick to pot and that’s all and all.
June 23, 2009 at 9:34 am
My sentiments exactly. Have you seen this? Fred Flinstone represents the hypocrisy.
June 21, 2009 at 6:30 am
“Chronic High Doses of Cannabinoids Promote Hippocampal Neurogenesis”
or chronic high doses of cannabinoids have an effect we can measure with the instruments we have today.
Tomorrow we can probably measure the effect of occasional low doses also. IMO the optimal way of using cannabis. Not for partying but for use in your creative work. Just a little bit every now and then to make you see things from another perspective.
also, I think Bill Hicks was spot on at 1:36 🙂
June 23, 2009 at 9:33 am
You mean the joke is funny? Or the part where God put drugs on the planet to speed up our evolution?
I have to say I am not too fond of either. But I don’t really like Stand-up comedy that much.
June 21, 2009 at 6:34 am
Drugs do not screw-up lives. |People do that to themselves in a variety of ways. Using cannabis for therapy is not the same as using it randomly for recreational experiences. Being wise about anything we ingest is the first step to using it for positive effects. Those of us who have used cannabis (myself for 30 years) for personal development are only too aware of the powerful positive effects – e.g. teaching me how to meditate effectively, how to do yoga for profound direct perception and personal change, how to self-actualise, to learn to juggle while riding a unicycle, to snowboard with grace and elegance, to connect deepy with my children’s way of seeing the world, to drum complex rhythms while singing and dancing and trancing, connected to deep brain processes, connected to deep subconscious and autonomic/parasympathetic processes. Entheogens are a natural part of the way humans do consciousness and apply our unique skills to the world. Spread the word wisely, tell people it is more than a ‘recreational high’ but a powerful agent for positive personal change.
June 21, 2009 at 9:32 am
Juggling while riding a unicycle?!? You can’t argue with that.
June 21, 2009 at 7:41 am
Do the endocannabinoids in this study include those that our body naturally synthesizes? If so, how can we promote our own internal production?
June 21, 2009 at 9:31 am
The endocannabinoids are those that our body naturally synthesizes. For the second question, I will have to get back to you on that.
June 21, 2009 at 8:43 am
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June 21, 2009 at 9:05 am
Interesting, thanks!
June 21, 2009 at 9:32 am
You’re welcome. Thank you for coming by.
June 21, 2009 at 9:48 am
I think that Allan moore fits well in this description, he has been a long term user and has some interesting ideas, just to show in practice that.
June 21, 2009 at 12:20 pm
I did like the Watchmen (the book I didn’t see the movie) and V for Vendetta (the movie, sadly I have not read the book).
Science. Why not?
June 21, 2009 at 10:28 am
I have never met a highly intelligent chronic pot smoker. I suppose that statement and the definition of “highly intelligent” is subject to debate.
June 21, 2009 at 10:57 am
How would you know? If they’re highly intelligent, and still indulging in an illegal activity, I’d expect them to hide it well. Sample selection bias is the bane of almost all discussions in this area.
June 21, 2009 at 12:21 pm
‘Sample selection bias is the bane of almost all discussions…”
Took the words right out of my mouth.
June 21, 2009 at 11:35 am
eh, duh..
June 21, 2009 at 11:55 am
If he is trying to say that somehow smoking pot makes you happy. He is wrong. it makes you dull. And unhappy whenever you are not smoking pot. which makes your whole life about smoking pot which makes you a loser..
June 21, 2009 at 12:25 pm
Actually, happiness was not once mentioned in this article. I just said that cannabinoids are the only illicit drug (including alcohol) that promote hippocampal neurogenesis with a chronic high dose treatment.
July 16, 2009 at 6:15 pm
If he is trying to say that somehow drinking makes you happy. He is wrong. it makes you dull. And unhappy whenever you are not drinking. which makes your whole life about drinking which makes you a loser..
Fixed that for you. Wait, sounds stupid, right?
Yes, Virginia, it is possible to be a casual smoker as much as it’s possible to be a casual drinker.
Besides, drinking has no good effect on the body, yet that’s legal.
Try breaking free of the DARE propaganda that’s been force-fed to you all these years. You don’t have to smoke it, but you don’t have to insist that everyone who does is a loser, either.
Have a nice day. 🙂
June 21, 2009 at 4:40 pm
[…] Chronic High Doses of Cannabinoids Promote Hippocampal … […]
July 4, 2009 at 11:08 am
Very interesting and informative. Thanks.
July 4, 2009 at 11:51 am
Thanks for stopping by.
November 30, 2009 at 6:22 pm
Politicians are 10 years behind the times when it comes to hemp use. People have been fighting for a long time against marijuana and pot prohibition with some movement going on now. Still too slow for those caught up in the jail system for possessing a little weed. Our freedoms have been trampled on by folks who know nothing about how beautiful cannabis can be for someones life, if one learns how to grow cannabis. Keep up the good work.
July 28, 2010 at 1:25 am
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November 11, 2012 at 12:53 am
Thank you for this very detailed information. As of I live in Seattle all of your data will be of very importance to all of us adults wether we choose to try Legal Marijuana or not.
January 7, 2013 at 4:33 pm
Seems to me that only Cannabidiol is potentially going to promote neurogenesis. THC on the other hand has shown to be very destructive to the brain structure. http://www.sciencedirect.com/science/article/pii/S0376871610003364 Plenty of other articles on scholar.
January 17, 2013 at 9:39 pm
[…] https://sciencewhynot.wordpress.com/2009/06/20/chronic-high-doses-of-cannabinoids-promote-hippocampal… […]
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