19 May 2004

"And furthermore Susan, I wouldn't be surprised to learn that they habitually smoke marijuana cigarettes --reefer"

Check out this story on Alternet about the history of biomedical research on marijuana and its biochemical effects.

Ongoing research conducted by Mechoulam, and his counterpart at the University of Buffalo, Herbert Schuel, shows that anandamides appear to be involved in regulating and balancing the body's biochemical systems, influencing or controlling the reproductive, sleep, fight-or-flight and appetite cycles.

"It's a quirk of nature that THC works on our receptors," Mechoulam remarked. "We were lucky to be the only group in the world working on this chemical." All mammals, fish, birds and reptiles seem to have anandamide-based regulatory systems; it's even found in cacao nuts, from which chocolate is made. "It is found in substantial quantities in chocolate, and may account for the feelings of pleasure that come from chocolate," Schuel said. Other researchers have found that chocolate seems to prolong the marijuana high – as pot users have long claimed.
In 1988, an American research group that included Bill Devane announced they had found evidence of a cannabinoid receptor in the mammalian brain. Devane joined Mechoulam in Israel to further research this question: Did our brains evolve to receive marijuana?

"We assumed that such a receptor does not exist for the sake of a plant compound," they concluded. Other drugs, like opium, had been found to bind at the molecular level to brain receptor sites intended for endorphins, the body's natural pain reliever. Mechoulam and Devane decided to look for the natural version of THC, and in 1992 they announced finding a fatty molecule that bound naturally to the cannabinoid receptor site
Anandamides are produced by our brains and bodies to achieve a sort of yin-yang biochemical balance, and do not produce the extreme "high" of marijuana, Mechoulam says.
"They're completely different, from a chemical point of view, from THC," he said. "But they combine in the receptor sites the same way." Anandamides are quickly broken down by the body after they have served their intended purpose, and do not last as long as THC metabolites, which remain in the body for weeks.
Anandamides play a survival role for young mammals – their instinctive suckling behavior seems integrally tied to the presence of anandamides. "If we block the system (from receiving anandamides), there is no suckling," Mechoulam explains.

I'm not sure how exactly this fits with some of the research on cannabinoids and pain I posted about earlier. Here's two comments:

First, though this article is about a year old, the research on cannabinoids and pain seems to have been pretty well established for several years (there's a bigger body of literature than I suspected when I originally posted here). Thus its odd that the article doesn't mention the endogenous cannabinoid-mediated system. It lists many other biological-processes; why not the role in pain?

Is it because (a) the experts discussed or the reporter is unaware of this role --in big research fields, right hands often don't know what left hands are doing; (b) the focus of the article is on anandamides and the role cannabinoids play with pain involve a different set of receptors and chemicals? If so, what are the relevant differences?

Also, as far as I understand it 'cannabinoids' are defined as (roughly) 'chemicals unique to cannabus', but the pain-literature talks about 'cannabinoid-receptors' and 'endogenous cannabinoids'. Does this mean that there are two classes of chemical here --anandamindes and cannabinoids-- or am I just confused?

Second, the article mentions something I've heard in several places before --that its a mystery why THC interacts with these systems of ours-- with the implications being that we somehow evolved to smoke weed. But if all this research is correct, there's no mystery here. No more than why we evolved to have ascorbic acid from citrus interact beneficially with us. Presumably, if there is any sense to the 'mystery', it turns on the fact that cannabinoids are unique to cannabus. That raises the first set of questions.

1 comment:

tim said...

Does this mean that there are two classes of chemical here --anandamindes and cannabinoids-- or am I just confused?

Anandamide is an endogenous cannabinoid. Cannabinoid receptors in the body are there to pick up anandamide but THC binds as well, cannabinoid receptors should be called anandamide receptors but anandamide was discovered afterwards. The whole system is in fact related to the opiate system - which is why increasing endogenous anandamide levels or introducing THC etc can have an analgesic effect.

The majority of neurotransmitter recepters have been found through drugs - opiates for instance are agonists for enkephalins in the body but morphine was found first. Drugs work on recepters in our body which for the most part are there to interact with substances we already have. The drugs often work better and longer than the substances we already have but this can also produce side effects.