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Cannabinoids Induce Brain Cell Growth? 494

Harlan writes "The Globe and Mail is reporting that researchers at the University of Saskatchewan are claiming that high doses of cannabinoids have induced new brain cell growth in the hippocampus, the part of the brain responsible for learning and memory, in rat subjects. There are some interesting potential implications in regards to high doses of cannabinoids found in substances like marijuana."
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Cannabinoids Induce Brain Cell Growth?

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  • by CRabe ( 895026 ) on Sunday October 16, 2005 @05:08AM (#13802105)
    The authors are far more cautious in their interpretation than some of the /. readers...but then this is not that much of a surprise. PDF (a few MBs) 1253627&blobtype=pdf []
  • by chinodelosmuertos ( 805584 ) on Sunday October 16, 2005 @05:22AM (#13802152)
    If you read TFA you'd have read that the original publication is due to be released in JCI, a peer reviwed journal that is quite high impact. Not Nature or Science, but not the Ulan Bator Journal of Basket Weaving Medicine either.
  • actual paper (Score:5, Informative)

    by geighaus ( 670864 ) on Sunday October 16, 2005 @05:25AM (#13802159)
    Actual paper can be found here [].
  • by Ron Bennett ( 14590 ) on Sunday October 16, 2005 @06:30AM (#13802317) Homepage
    What a surprise to click on Slashdot and see news about cannabinoids - I feel like I'm reading my own site ...

    I operate CANNABIS.COM ... shortcut url []

    Some informative pages to check out:

    Lots of cannabis Research information *with sources listed* []

    TR-446 Toxicology and Carcinogenesis Studies of 1-Trans-Delta9-Tetrahydrocannabinol (CAS No. 1972-08-3) in F344 Rats and B6C3F1 Mice (Gavage Studies) []
    (mirror of the study published by the U.S. National Toxicity Program)

    Cannabis News []

    And finally, Erowid's Cannabis Vault... ml []

    Ron Bennett
  • by Anonymous Coward on Sunday October 16, 2005 @06:41AM (#13802354)
    See subject. And last sentence of parents post...
  • No (Score:1, Informative)

    by Anonymous Coward on Sunday October 16, 2005 @06:56AM (#13802402)
    Head Shop= Place that sells pipes, papers, vapes, and other hippy stuff.

    Coffee Shop= Pot bar.

  • by lysergic.acid ( 845423 ) on Sunday October 16, 2005 @07:19AM (#13802452) Homepage

    Actually, the research talks about "cannabinoids." Cannabinoids are the primary psychoactive alkaloids contained in cannabis, of which, THC is the most concentrated in most strains, although each strain contains different levels of each. THC is a cannabinoid so it likely has very similar pharmacological effects as HU-210.

  • by lysergic.acid ( 845423 ) on Sunday October 16, 2005 @08:16AM (#13802596) Homepage
    that's a bad analogy. we're not talking about two substances that simply have similar chemical properties. we're talking about two alkaloids that have similar pharmacological properties. a closer analogy would be comparing two different kinds of exogenous opioids like diacetylmorphine(heroin) and morphine, or codeine and morphine, or a fentanyl analog and morphine, etc., all of which activate a shared set of receptors in the brain. cannabinoids also share a lot of common receptor sites with each other--by definition--thus they're more likely to have similar pharmacological actions. ethanol and methanol don't bind to neurotransmitter receptors in the brain.
  • by hackstraw ( 262471 ) * on Sunday October 16, 2005 @08:34AM (#13802656)
    Besides, you can be sure that with such a hot subject and the way research is financed/politiced there will be more research 'debunking' this even if it turns out to be true after all.

    Yeah, they probably were studying MDMA ("ecstasy") this time. []
  • by O.W.M ( 884392 ) on Sunday October 16, 2005 @08:47AM (#13802695)
    Ethanol and Methanol DO have roughly the same effect. You get the same intoxication from both of them. What kills you is not the methanol intoxication but the methanol hangover.

    Methanol is metabolized by alcohol dehydrogenase (ADH) via formaldehyde to formic acid, being responsible for the metabolic acidosis in methanol poisoning.

    That's why ethanol is given as a cure for methanol poisoning; by adding ethanol to the bloodstream the metabolization rate of methanol decreases as the body will also metabolize ethanol, and thus the level of toxic methanol byproducts in the blood will be kept at a non-lethal level.

  • by nietsch ( 112711 ) on Sunday October 16, 2005 @08:55AM (#13802722) Homepage Journal
    Did you read the article? That is where I got my info from.
    And FYI: the aargument was if cannabis causes brain cell growth, not if weed is good or bad.
    And as for my bias: I've grown about a kilo of the stuff over the years. Does that make my bias clear?
  • by nietsch ( 112711 ) on Sunday October 16, 2005 @10:05AM (#13802997) Homepage Journal
    from TFA:
    They found that giving rats high doses of HU210 twice a day for 10 days increased the rate of nerve cell formation, or neurogenesis, in the hippocampus by about 40%.

    Are you still sure that the only method they used was injecting cannabinoids and measuring how much they ate?

    I guess that experiment is an accepted test for anxiety, and prozac cum suis scores very good on it. Science gets better if you use standard test where you can. Even though your 'munchies' hypothesis sounds plausible, it still cannot explain the neurogenesis bit.
  • by nietsch ( 112711 ) on Sunday October 16, 2005 @10:11AM (#13803012) Homepage Journal
    Because I like to amuse you so much, i'll cite it for you:
    In another study, Barry Jacobs, a neuroscientist at Princeton University, gave mice the natural cannabinoid found in marijuana, THC (D9-tetrahydrocannabinol)). But he says he detected no neurogenesis, no matter what dose he gave or the length of time he gave it for. From this [] New Scientist article.

    Happy now?
  • by dborod ( 26190 ) on Sunday October 16, 2005 @11:06AM (#13803310) Homepage
    There was an interview on Friday evening on the CBC show As it happens with Jamie Van Cleemput, one of the scientists on the team. There is a link on this page 5/10/14.html [] to an audio file that contains the interview 14-aih1.ram []
  • by Ellis D. Tripp ( 755736 ) on Sunday October 16, 2005 @11:31AM (#13803432) Homepage
    Lysergic acid is an intermediate in the synthesis of LSD.

    LSD is lysergic acid diethylamide.
  • by xanadu113 ( 657977 ) on Sunday October 16, 2005 @12:24PM (#13803731) Homepage
    What makes you think everyone who uses cannabis medically smokes it? Allow me to destroy some stereotypes here. Cannabis can be taken the following ways:

    Baked into foods (no pun intended)
    Vaporized (my method of ingestion, no pyrolytic compounds since it's not burning it.)

    Cannabis has also been made into various oils and lotions for putting directly on the skin. There is even discussion that it was used in the traditional hebrew annointing oil.

  • Re:Good Grief (Score:3, Informative)

    by xanadu113 ( 657977 ) on Sunday October 16, 2005 @12:52PM (#13803931) Homepage
    Ever heard of a vaporizer?

    It heats the herbs of your choice, to a point that releases the medicinal compounds, without creating pyrolytic compounds.

    A very affordable Vaporizer can purchased here [] I have one and am VERY happy with it.

  • Re:Good Grief (Score:2, Informative)

    by hazah ( 807503 ) on Sunday October 16, 2005 @01:06PM (#13804009)
    Oh please, how about the fact you inhale most of those things everywhere you go? And you didn't just compare weed to tobacco, did you? Tobacco these days is loaded with unnatural chemicals so that you get that smooth continuous burn, preservatives that will not allow mold to form, and the fields are fertilized extensively with, what I suspect to be, the cheapest solution. What are you basing your opinion on? I don't get it. Maybe it's those bong hits I've been taking, eh? _effects_of_cannabis#Smoking/ []

  • by thegnu ( 557446 ) <thegnu @ g m a i l . com> on Sunday October 16, 2005 @01:28PM (#13804161) Journal
    But the bumbling ineptitude and stupidity of the typical stoner campaigner is a damning indictment of the negative effects of marijuana.

    I think it has a lot to do with the fact that one side has high-powered rifles and amphetamines and is fighting a WAR AGAINST A PLANT by shooting the people who like the plant, and the other side just likes the stupid plant. Also, does it not seem weird to you that one might be put in a cage with murderers for smoking pot? It seems kind of harsh.

    If the government would stop shooting people for carrying plants around with them, then the druglords wouldn't be in business. And I could get my pot from someone who wasn't a criminal, and my life would be safer, but people would rather make money off the loss of liberty of the largely peaceful masses than have them be safe.
  • by syukton ( 256348 ) on Sunday October 16, 2005 @01:30PM (#13804175)
    I read this feed on forbes [] three days ago. It contains more information, including: "Autopsies revealed that by the end of the 10-day HU210 treatment regimen, new neurons had been generated and integrated into the circuitry of the hippocampus region of the rat's brains. This process, known as neurogenesis, was still in evidence a full month after treatment had been initiated."

    So you see, they're actually basing it on autopsies, which tend to involve cutting open dead creatures and poking around their insides looking at what's going on. I think they actually MEASURED the number of brain cells and found more in the treated rats. Pretty fancy huh, scientists measuring things?! heh.
  • Re:Good Grief (Score:2, Informative)

    by fafalone ( 633739 ) on Sunday October 16, 2005 @02:10PM (#13804416)
    Well let's start with Fried et. al. [], who concluded that ongoing heavy use of marijuana has a signficant negative impact on IQ.

    And then we can in fact see the short term memory impairment,
    Heyser, C.J.; Hampson, R.E.; and Deadwyler, S.A. Effects of delta-9-tetrahydrocannabinol on delayed match to sample performance in rats: Alterations in short-term memory associated with changes in task-specific firing of hippocampal cells. Journal of Pharmacology & Experimental Therapeutics 264(1):294-307, 1993.

    And let's not pretend that smoking marijuana isn't going to have a negative effects on the lungs,
    Tashkin, D.P. Pulmonary complications of smoked substance abuse. West J Med 152:525-530, 1990., and
    Sarafian, T.A.; Magallanes, J.A.; Shau, H.; Tashkin, D.; and Roth, M.D. Oxidative stress produced by marijuana smoke. An adverse effect enhanced by cannabinoids. Am J Respir Cell Mol Biol 20(6):1286-1293, 1999.

    Or the immune system
    Srivastava, M.D.; Srivastava, B.I.; and Brouhard, B. Delta-9 tetrahydrocannabinol and cannabidiol alter cytokine production by human immune cells. Immunopharmacology 40(3):179-185, 1998.

    Marijuana capable of producing psychotic symptoms? Yes.
    Fergusson, David M., John Horwood & Elizabeth M. Ridder, "Tests of Causal Linkages Between Cannabis Use and Psychotic Symptoms," Addiction, Vol. 100, No. 3, March 2005, p. 363.

    The original poster was talking about chronic use, implying ongoing, so let's also examine the effects of current intoxication: Learning and memory are in fact impaired by cannabis:
    Grant, Igor, et al.,(2003) "Non-Acute (Residual) Neurocognitive Effects Of Cannabis Use: A Meta-Analytic Study," Journal of the International Neuropsychological Society. Cambridge University Press, 9, p. 685.

    Long term permanent damage? Absolutely, but only to the lungs.
    Negative impacts on the brain during ongoing use? Absolutely.
    Maybe you ought to be familiar with the research yourself before attacking other people? This is just a tiny fraction of all the research conducted. A simple 5 second google search would have turned up all you needed to know to not look like the jackass you do now.
  • Re:Good Grief (Score:5, Informative)

    by Anonymous Coward on Sunday October 16, 2005 @03:08PM (#13804747)
    From the conclusion of your first article:

    Current marijuana use had a negative effect on global IQ score only in subjects who smoked 5 or more joints per week. A negative effect was not observed among subjects who had previously been heavy users but were no longer using the substance. We conclude that marijuana does not have a long-term negative impact on global intelligence. [emphasis added]

    As for the hyperbole of your other claims, let's dispose of them by referring to the most-widely used medical textbook in the world, The Merck Manual of Diagnosis and Therapy [] entry on marijuana:

    Critics of marijuana cite much scientific data regarding adverse effects, but most of the claims regarding severe biologic impact are unsubstantiated, even among relatively heavy users and in areas intensively investigated, such as immunologic and reproductive function. However, high-dose smokers of marijuana develop pulmonary symptoms (episodes of acute bronchitis, wheezing, coughing, and increased phlegm), and pulmonary function may be altered. This is manifested by large airway changes of unknown significance. Even daily smokers do not develop obstructive airway disease. Pulmonary carcinoma has not been reported in persons who smoke only marijuana, possibly because less smoke is inhaled than during cigarette smoking. However, biopsies of bronchial tissue sometimes show precancerous changes, so carcinoma may occur. In a few case-control studies, some tests detected diminished cognitive function in small samples of long-term high-dose users; this finding awaits confirmation. Studies in newborns have not found evidence of fetal harm due to maternal use of cannabis. Decreased fetal weight has been reported, but when all factors (eg, maternal alcohol and tobacco use) are accounted for, the effect on fetal weight disappears. delta-9-Tetrahydrocannabinol is secreted in breast milk. Although no harm to breastfed babies has been shown, breastfeeding mothers, like pregnant women, are advised to avoid using cannabis. [emphasis added]

    Btw, I am not sure why you have to call the poster you are responding to names. Seems like your arguments should be able to stand on their own.
  • A glimmer of hope (Score:2, Informative)

    by lordvalrole ( 886029 ) on Sunday October 16, 2005 @03:34PM (#13804887)
    I work in the video game industry (for a big company I shall not name...its not EA) and something about our industry is extremely great. The fact that a huge percentage of us (people who create the games, and well the people who play the games) smoke pot. I don't understand why it's such a big deal. Smoking was one of the things that kept me sane working 70-80 hour work weeks and 15 hour days during crunch. I smoked before work and drove through LA traffic (anyone who lives near or around LA knows how crappy it is). I did this for about 7 months straight of just smoking 4 to 10 to 15 times a day and it didnt have an affect on me. Infact I am in my home town right now with out any and I havent had a withdrawl once. No cravings or anything like that. The thing about pot is that is not physically addicting to people is physiologically addicting to people. People love it so much they want more of it, just like sex or anything else. Smoking tobacco and drinking alcohol is far worse for your health and your stability than smoking cheeba. I really really want to make a "Truth" ad about smoking marijuana. I want it to be posted all over the internet and all over tv. The truth that marijuana isnt as bad as eating at McDonalds or KFC. Too bad pot isn't legalized because it would be safer and free up some jail space. That wont happen because a lot of pharmaceutical companies would prolly be out of business. What needs to change is the overall view that marijuana is bad. The media has those anti-drug ads against marijuana. I think we need pro-marijuana ads. America believes what they see and hear on TV (its sad). Just about everything we see and here stems from about 10 major corporations. Sony, AOL/Timewarner, news corp, Disney, the list goes on. If anything is going to change here, we actually need to start doing crap about it, imho.
  • by Anonymous Coward on Sunday October 16, 2005 @05:02PM (#13805355)
    Although you don't mention it, the first link shows only a minor 4.1 pt decrease and only for heavy current users. Moderate and former users showed an increase greater than non-users - 5.8 and 3.5 vs 2.6 pts, respectively.

    Inhaling smoke of any kind is, of course, not good for your lungs. There are other admittedly less popular means of administration.

    It does appear that marijuana may cause immune system depression, but the extent and ways in which it does so is still being researched. This article [] explores the counter-viewpoints. Another study [] has shown a decrease in tumor resistance with injected THC in rats, but I'm not sure of the doses. It should be noted as well that in some people, like MS patients, a supressed immune system can be a good thing [].

    Although psychotic symptoms can be produced by Cannabis consumption, it's certainly not typical. Just as some people have severe reactions to peanuts, some may have psychotic reactions to Cannabis. However, due mainly to heavy restrictions on studies, we still don't know much about endocannabinoids' role in the nervous system and the actions of various cannabinoids. This study [] suggests that endocannabinoids may actually prevent psychosis; since smoking Cannabis would cause stimulation of endocannabinoid receptors, cannabinoids may be useful in preventing psychosis. Or, it might further reduce your body's production of endocannabinoids and lead to greater psychotic effects when you quit smoking. Or something else, it's hard to say at this point. Research is still being done, however, and I certainly wouldn't suggest getting high to get rid of psychotic symptoms - in fact, I would actively advise against it.

    I can't read your memory and learning study, so I can't really comment on it. Cannabinoids certainly have been shown to impair memory and learning in various degrees under different circumstances, but their role [] - believed to be effected in the hippocampus - may, as this article (the one the post is on) may have positive effects as well.

    Conclusion: Cannabis is not a panacea. It should come as no surprise to anyone that there are both good and bad sides to Cannabis - as with all medicine, as with everything. It's absurd to pretend that there are no negative effects, but it's also absurd to pretend like we have all the answers. We have to keep researching, and we have to make sure the government allows needed research. That being said, overall, cannabis has relatively few and insubstantial side effects compared to other drugs, and it's ridiculous beyond comprehension that it's a Class I substance.
  • Re:Good Grief (Score:3, Informative)

    by morganjharvey ( 638479 ) on Sunday October 16, 2005 @06:12PM (#13805676)
    You mean:

    Marijuana Use and Depression, Brian E. Green; Christian Ritter, Journal of Health and Social Behavior, Vol. 41, No. 1. (Mar., 2000), pp. 40-49.

    College Student Marijuana Use and Societal Alienation, R. C. Knight; J. P. Sheposh; J. B. Bryson, Journal of Health and Social Behavior, Vol. 15, No. 1. (Mar., 1974), pp. 28-35.

    Marijuana ``Justifies Serious Concern'', Thomas H. Maugh, Science, New Series, Vol. 215, No. 4539. (Mar. 19, 1982), pp. 1488-1489.

    Marijuana: Harder Than Thought?, Ingrid Wickelgren, Science, New Series, Vol. 276, No. 5321. (Jun. 27, 1997), pp. 1967-1968.

    Phytohemagglutinin-Induced Lymphocyte Transformation in Humans Receiving 9 -Tetrahydrocannabinol, R. Jane Lau; David G. Tubergen; Mason Barr, Jr.; Edward F. Domino; N. Benowitz; Reese T. Jones, Science, New Series, Vol. 192, No. 4241. (May 21, 1976), pp. 805-807.

    Normal Skin Test Responses in Chronic Marijuana Users, Melvin J. Silverstein; Phyllis J. Lessin, Science, New Series, Vol. 186, No. 4165. (Nov. 22, 1974), pp. 740-741.

    I can go on if you'd like...
  • by dryeo ( 100693 ) on Monday October 17, 2005 @02:57AM (#13807601)
    You do realize that there are other ways to ingest pot besides smoking it don't you?
    I've known a few people who won't smoke anything but they sure loved their marijuana cookies.

Someone is unenthusiastic about your work.