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2002-08-03 kl. 15:48 #727reaperDeltagare
Attack of the munchies
Raiding the fridge in the middle of the night is an all too common side-effect of smoking cannabis. But you don’t have to smoke dope to get the munchies. Certain chemicals you’re born with can spark off an attack of hunger as well.
Even the most upright citizens have naturally occurring cannabis-like molecules circulating in their brains. Now scientists are suggesting that these molecules trigger intense hunger pangs and may even contribute to obesity.
Normally, mice that have been starved eat voraciously. But George Kunos and his colleagues at Virginia Commonwealth University in Richmond found that the absence of cannabis receptors makes the mice much less hungry.
Genetically modified mice lacking the receptors ate far less food than usual after being starved for 18 hours, as did unmodified mice that had been given drugs to block the receptors.
But you can have too much of a good thing. In a finding that could link cannabinoids to human obesity, Kunos and his team found high levels of cannabis-like substances in the brains of excessively fat mice. The mice were born with a genetic defect that prevented them from making leptin, a hormone that is known to have a key role in curbing appetite.
It was the discovery of leptin’s role that transformed obesity research in the 1990s. But how the hormone tones down hunger has never been quite clear. Now Kunos believes naturally occurring cannabinoids could be a vital piece of the puzzle.
In its latest experiments, his team has found that injecting leptin into rats and mice automatically led to a sharp drop in cannabinoid levels.
The finding backs up earlier work by Raphael Mechoulam and his colleagues at the Hebrew University in Israel, who found that injecting newborn mice with drugs that neutralise the effect of cannabis dramatically depressed the mice’s appetite. The mice stopped suckling and died.
So could too much natural cannabinoid in the brain make people fat? ”It’s reasonable to speculate that it contributes to some forms of obesity,” says Kunos. ”But so far we have no direct evidence.”
In France, though, scientists are already giving obese people an experimental drug designed to block cannabinoid receptors. In a trial lasting 16 weeks, a compound codenamed SR141716 was given to the patients to see if it would help curb their hunger pangs.
The full results won’t be revealed until later this year, but Francis Barth of the Montpellier-based drugs company Sanofi-Synthelabo, which ran the study, says the patients lost more weight than a control group.
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