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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
Making Sense of the Munchies
11 April 2001 7:00 pm
Bill Clinton may not know it first hand, but millions of marijuana smokers who have inhaled claim that cannabis boosts their appetite. Now, new results show how the brain's own cannabis-like compounds can lead to late-night refrigerator raids. The results may lead to new drugs to control obesity or boost the appetite of anorexics and cancer patients treated with chemotherapy.
Appetite is regulated by more than a half dozen molecular signals, all working together in ways that still are not well understood. Cannabis boosts appetite in rats and mice; because the brain makes its own cannabis-like molecules, called cannabinoids, pharmacologist George Kunos of the National Institute on Alcohol Abuse and Alcoholism in Bethesda, Maryland, and his colleagues asked if cannabinoids help regulate appetite.
The hunch was right, the researchers report in the 12 April issue of Nature. Genetically engineered mice whose brains lacked a receptor needed to sense cannabinoids didn't have healthy appetites: They ate about 40% less, on average, than normal mice. And a drug that blocked the action of cannabinoids led normal mice to eat only as much as the mutant animals.
The cannabinoids seem to be a key part of the neural circuit that regulates appetite, Kunos says. Obese mice and rats that can't make leptin, an important appetite-regulating hormone, showed higher levels of two cannabinoids in the hypothalamus, a brain region where leptin is thought to act. Kunos says that drugs that block or boost cannabinoid signaling could alter people's appetite.
"I think it's very exciting work ... that reveals an unexpected connection [between leptin] and endogenous cannabinoids," says pharmacologist Daniele Piomelli of the University of California, Irvine. And he and other researchers say that while hurdles still remain, the findings boost hopes that a cannabinoid-blocking drug could be used to treat obesity.