The effect of Cannabis on the formation or disruption of neural circuits

[Vanadium Gryllz]

So I came across this paper recently: http://www.jneurosci.org/content/36/26/7039

From https://www.sciencedaily.com/releases/2016/09/160912111913.htm

Researchers have clarified important mechanisms involved in the formation of neural circuits in the brain. This group also discovered that delta-9-tetrahydrocannabinol (THC), a psychoactive substance also found in cannabis, causes disruption of neural circuits within the cortex. These results explain why cannabis may be harmful and have potential to find application in the functional recovery of brain injury and in cases of dementia.

But a) I don't know anything about neuroscience
and b) I don't have access to the paper

I would be interested in hearing the views of our resident expert(s) on the findings.

On the other side of the coin, there's been another cross-parliamentary group recommending legalisation for medicinal purposes in the UK, a high CBD strain is apparently available in Switzerland, Germany is making rumblings and more US states have got some form of legalisation on the ballot this (or next?) year.

[Junkenstein]

Oh shit.

If this turns into DRUGSANDDRUGSANDDRUGS for 300 pages I'm going to hunt you down.

If you are RWHN in disguise, admit it now please so I can just start posting the photo.

Please don't be RWHN.

[Vanadium Gryllz]

Fear not, I am not RWHN.

I am definitely pro-weed but it's interesting to hear some potential 'cons'. It's interesting that this paper is coming out of Japan, a country that I thought was particularly anti-drugs. Does that have an effect on the findings or interpretations within?

The parliamentary proposal that I mentioned above is promising and has generated some good (as in, pro-legalisation) articles in various news places including the BBC. However I don't have much hope for any change happening any time soon in the UK.

[Junkenstein]

OK, I'll take a look.

[Junkenstein]

Hmm.

http://resou.osaka-u.ac.jp/en/research/2016/20160630_1

clarified that multiple mechanisms were involved in the formation of neuronal circuits in the cerebral cortex. This group also clarified that a substance similar to cannabinoid, an active substance of cannabis, played an important role in the formation of neuronal circuits, and that the intake of cannabis pruned even necessary synapses, destroying neuronal circuits, a world first.

That seems new and it'll be interesting to see how the pro-pot lobby react to it. I'm taking it on good faith that it's solid science and peer reviewed etc. I'm not up on how rife corruption and collusion in Japanese academic and political circles is like nowadays but I'll allow for the possibility.

This group's achievement clarified scientific grounds that cannabis and intoxicating drugs had adverse effects on the brain. By disabling the functions of cannabinoid, it may be possible to suppress the breakdown of neural circuits. It is expected that this group's achievement will be used for recovering functions impaired by brain damage and dementia.

Doesn't seem like anything particularly new here, just more substantiation of known good/bad.

From the significance statement:

, ...caused  retraction of thalamocortical axons, suggesting that cannabinoids translate physiological changes into morphological consequences.

So that puts us back to "could be useful, depending on the ailment you're trying to treat." In some cases this will be desirable, others not. That's a layman's read of it, anyway. 

[Mesozoic Mister Nigel]

I should be able to get the article, but it'll have to wait until I get back from Manitoba because I have to leave at like 5:30 in the morning tomorrow. The conclusion sounds overstated to me; it sounds more like they identified a mechanism through which harm is possible, rather than proved that harm occurs.

[minuspace]

I mean, is this some fancy way of saying it interferes with working memory (as in, just forget about optimal efficiency for your Imperial surplus labour meat robots)?  Because if they were going to clarify how anything does so, the above quotes provide no such indication.  LuciferX gives this 3 Fishy-Axis-Power-PointS.

[Mesozoic Mister Nigel]

I looked the article over and, as I suspected, the findings demonstrate a mechanistic avenue by which exogenous cannabinoids can disrupt axon-dendrite connections, but does not show that exogenous cannabinoids inhibit network formation, and the authors are very clear that more research is necessary to come to any such conclusion.

[Vanadium Gryllz]

Thanks for your input guys. I suppose most research should really be prefixed with "...but more research is necessary." And probably journalists who do science reporting need to have it branded onto the backs of their hands.

I guess there's gonna be an explosion in research into the effects of exogeneous cannabinoids on the endocannabinoid system (and probably the endocannabinoid system in general) in the coming years. It will be interesting to see the results.

Is the endocannabinoid system a well-defined system in the way that the nervous and circulatory systems are or is it more of an umbrella term for any cells with cannabinoid receptors and there interactions therein?

[Mesozoic Mister Nigel]

Thanks for your input guys. I suppose most research should really be prefixed with "...but more research is necessary." And probably journalists who do science reporting need to have it branded onto the backs of their hands.

I guess there's gonna be an explosion in research into the effects of exogeneous cannabinoids on the endocannabinoid system (and probably the endocannabinoid system in general) in the coming years. It will be interesting to see the results.

Is the endocannabinoid system a well-defined system in the way that the nervous and circulatory systems are or is it more of an umbrella term for any cells with cannabinoid receptors and there interactions therein?

It's not well-typified at all, at this point. But then again, neither are any of our cell signaling systems. The level of complexity is utterly staggering, and we've only really had the technology to look at these systems for a few decades.

Sort of an overview is that there are different types of receptors and different types of cell, as well as a number of types of cannabinoid, about which little is known. The function of a cannabinoid depends on the cell and receptor type, and the kind of signaling cascade it triggers, and the nature of the cells it signals to. Variations at any step mean differences in function.

To put the amount of work it will take to understand the whole system into perspective, a single researcher might spend two to five years trying to figure out what one receptor type in one cell type does, and that only answers the question for that cell type.

[Vanadium Gryllz]

Could take a while to figure it all out then.

[Mesozoic Mister Nigel]

Could take a while to figure it all out then.

Yep.