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Can someone confirm if this is true, if so that is kinda sad since i smoke alot

A

Anima Insania

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http://www.biopsychiatry.com/cannabinoids.htm

The effects of cannabinoids on the brain
by
Ameri A
Department of Pharmacy and
Pharmacology of Natural Compounds,
University of Ulm, Germany.
Prog Neurobiol 1999 Jul; 58(4):315-48

ABSTRACT
Cannabinoids have a long history of consumption for recreational and medical reasons. The primary active constituent of the hemp plant Cannabis sativa is delta9-tetrahydrocannabinol (delta9-THC). In humans, psychoactive cannabinoids produce euphoria, enhancement of sensory perception, tachycardia, antinociception, difficulties in concentration and impairment of memory. The cognitive deficiencies seem to persist after withdrawal. The toxicity of marijuana has been underestimated for a long time, since recent findings revealed delta9-THC-induced cell death with shrinkage of neurons and DNA fragmentation in the hippocampus. The acute effects of cannabinoids as well as the development of tolerance are mediated by G protein-coupled cannabinoid receptors. The CB1 receptor and its splice variant CB1A, are found predominantly in the brain with highest densities in the hippocampus, cerebellum and striatum. The CB2 receptor is found predominantly in the spleen and in haemopoietic cells and has only 44% overall nucleotide sequence identity with the CB1 receptor. The existence of this receptor provided the molecular basis for the immunosuppressive actions of marijuana. The CB1 receptor mediates inhibition of adenylate cyclase, inhibition of N- and P/Q-type calcium channels, stimulation of potassium channels, and activation of mitogen-activated protein kinase. The CB2 receptor mediates inhibition of adenylate cyclase and activation of mitogen-activated protein kinase. The discovery of endogenous cannabinoid receptor ligands, anandamide (N-arachidonylethanolamine) and 2-arachidonylglycerol made the notion of a central cannabinoid neuromodulatory system plausible. Anandamide is released from neurons upon depolarization through a mechanism that requires calcium-dependent cleavage from a phospholipid precursor in neuronal membranes. The release of anandamide is followed by rapid uptake into the plasma and hydrolysis by fatty-acid amidohydrolase. The psychoactive cannabinoids increase the activity of dopaminergic neurons in the ventral tegmental area-mesolimbic pathway. Since these dopaminergic circuits are known to play a pivotal role in mediating the reinforcing (rewarding) effects of the most drugs of abuse, the enhanced dopaminergic drive elicited by the cannabinoids is thought to underlie the reinforcing and abuse properties of marijuana. Thus, cannabinoids share a final common neuronal action with other major drugs of abuse such as morphine, ethanol and nicotine in producing facilitation of the mesolimbic dopamine system.
 
Maybe it needn't be simplified, it would seem that the main point was about neurotoxicity and a bit about addictiveness.
 
not a doctor, but from what i understood of that jibberish is that its only saying it plays a role in dopamine levels of the brain (so does playing certain video games i.e. evercrack), and yes that is a shared trait among most drugs. but i've done opiates and other drugs that obviously impact the levels to a far greater extent i would assume. all i'm sayin is that article is placing the drugs way too close together imo.
the writer is either biased or needs to smoke weed then try morphine and rewrite it.
 
That article has a lot of crap in it. That's why it's published in a shitty journal like 'biological psychiatry'.

Yes, cannabis does cause brain cell death, but not conclusively so in whole animals, just in, in vitro situations.

Yes cannabinoids effect the "reward" pathway in the same way morphine does. But that still doesn't mean its addictive.
 
^^ Yes indeed, it was a little hard to understand but I generally got what it was talking about. Don't really see how it proves that MJ has a severe addiction potential. It you just can't compare it to something like opiates.

Yet another biased report by someone who no doubt has never smoked cannabis.

Cheers,
pullacone
 
Its a review article frizzantik, they don't gather any information. But the people they cite are (just off the top of my head):
Neurotoxicity = Chan et al., 1998
CB2 = Munro et al., 1993
Anandamide = Devane et al., 1992
Dopamine = ? probably Tanda et al., 1997

Pullacone: It dosen't claim that cannabis has a severe addiction potential. What it claims is absolutely correct.
 
Has there ever been a study to associate marijuana and brain cell damage in humans or even monkeys that were exposed to average amounts of smoke (not extremes)?

As for any implications possibly made by that last comparison, pot is addictive just like some people find football addictive. Anything is addictive it just takes the right person to become overly absorbed. Of course direct chemical methods are usually easier, more seductive, and very reinforcing.
 
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BilZ0r said:
That article has a lot of crap in it. That's why it's published in a shitty journal like 'biological psychiatry'.
Click to expand...

Eh, that's *hardly* a "shitty journal" ;)

And it's not like they wrote it, either, it was written by

Ameri A
Department of Pharmacy and
Pharmacology of Natural Compounds,
University of Ulm, Germany.
Prog Neurobiol

www.biopsychiatry.com contains more info than most people here would be willing or able to absorb, but give it a shot and you just might be fascinated at how our brain works. It's mostly written from the point of view of someone that wants to improve their lives chemically, but of course that means listing pros and cons of substances.

All in all, you won't find a site more scientific while at the same time sympathetic to the human need for euphoria.

--- G.
 
Anima Insania said:
Thus, cannabinoids share a final common neuronal action with other major drugs of abuse such as morphine, ethanol and nicotine in producing facilitation of the mesolimbic dopamine system.
Click to expand...

This doesn't mean they've compared it to something like opiates. They share a common neurological action, as does nicotine..
 
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There has been no evidence that cannabinoids kill brain cells in whole animals, but there has been a lot of evidence that shows that it permanently alters the way cells are connected and that this is associated with negative behavioral changes.

Its also a fact, that THC kills neurons in culture or brain slices.

Cannabinoids share much more than nicotine alcohol or cocaine. Its quite odd, I wish someone would explain it, I'll post more about it if someone is curious.

Your getting confused, biopsychiatry.com isn't a journal, its an web site run by BLTC.com, who is a front for a guy who likes to report weird references to show that if we fuck with out brain we can be happy all the time, and that that would be a good thing.

Biological Psychiatry is a journal completely unassociated with biopsychiatry.com. And its not a very good journal.
 
I am glad that it is true, i think also that it in some conditions even can protect the neurons from damage!

From antioxidants and maybe elevated Melatonin who is a Antioxidant-neurotransmitter-hormone
 
Yes. Cannabis protects neurons from several kinds of insults. I doubt it has much to do with melatonin.
 
"The drug is really quite a remarkably safe one for humans, although it
is really quite a dangerous one for mice and they should not use it."
J.W.D Henderson
Director of the Bureau of Human Drugs, Health and Welfare, Canada

i found that a intersting. i mean how many test do they do on people and not mice?
 
Has there ever been a study to associate marijuana and brain cell damage in humans or even monkeys that were exposed to average amounts of smoke (not extremes)?
Click to expand...

The only study I've seen that shows neurotoxicity was with mouse cells in culture (the Chan study). Questions about this study include whether the concentrations of THC they squirted in the dish were really what you would see in humans and how close the mechanisms that caused cell death in the mouse are to those that would cause cell death in humans. Vitamin E completely inhibited the cell death, so eat your multivitamins! I wonder whether other free-radical munchers are present in the brain, easily protecting the neurons? It would explain why they haven't found any brain cell death with in vivo studies at realistic inhalation levels in adult monkeys.

As for addiction, it looks like THC activates the same reward pathway as alcohol, morphine, and cigarettes. Also sex, good food, a nice hot tub, a good run, etc. etc. Addiction studies show that weed activates somewhat less strongly than alcohol, but that it can have some addictive properties.

Cognitive studies in humans have shown that there are some persistent subtle effects on sound processing and short-term memory out through 36 hours. After that, no one has found any differences yet except that smokers who volunteer for studies tend to be low-income and depressed (yep, that was a paper). If there are any permanent effects of moderate use, they are very subtle.

So, weed isn't, say, nearly as dangerous as alcohol, but you can't toke 20 times a day without any negative effects. There are no things that work that way, even healthy things like exercise. I think you should respect it almost as much as you respect alcohol (i.e. you wouldn't drink a six-pack every night, so don't smoke 3 bowls every night) and you'll be ok.
 
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I don't think there is a study which compares THC and alcohol in regards to their activation of the 'reward' pathway.

The dose Chan used to kill brain cells in vitro was very comparable to the dose humans would recieve, in fact, the lowest toxic does was much lower the your average brain concentration of THC.

There are plenty of free radicle scavengers in both culture and whole animal situations, but something must be different, I wonder what. Perhaps glial cells, but I doubt it.
 
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