Blocking a Marijuana-Like Brain Chemical Helps Mice Stay Slim

Blocking 2-AG in the brain helped mice stay slim. (Getty Images)

Blocking a marijuana-like chemical in the brain could help fuel effortless  weight loss, according to a new study on mice.

Researchers at the University of California at Irvine engineered mice to have lower brain levels of the endocannabinoid 2-AG, a compound similar to tetrahydrocannabinol (THC) believed to help regulate  metabolism.

"Endocannabinoids are our own marijuana-like chemicals. We make them, our brains make them," said study author Daniele Piomelli, a professor of pharmacology at UC Irvine. "Their role in the brain is to control body metabolism outside the brain."

The modified mice ate more and moved less than their unmodified counterparts without gaining weight, even when they were fed a high-fat diet.

"These mice had what really looked like a much faster metabolism than normal mice. They burned fat calories more efficiently," said Piomelli. Specifically their brown fat, a type of fat that keeps mammals warm, became hyperactive, converting to heat much quicker than in normal mice.

Despite their dismal diet and nonexistent exercise routine, the modified mice showed no signs of metabolic syndrome - a group of conditions that include  high blood pressure and insulin resistance that up the risk of heart disease, stroke and diabetes.

"It was really very striking," said Piomelli. "Striking for all of us who struggle to maintain our weight or lose some."

The study was published today in the journal Cell Metabolism.

Piomelli said he hoped to develop drugs that could selectively diminish levels of 2-AG in the brain and, in doing so, "boost our capacity to burn fat calories." But don't ditch the gym membership yet, he warned. Developing the drug could take years.

"It's not easy but certainly feasible," Piomelli said. "First, we need to really study the mice to make sure there are no unwanted side effects. We don't want to waste time developing drugs that can cause more harm than good."

In the meantime, people who want to lose weight should focus on eating less and moving more.

"There's no magic bullet anywhere," said Dr. Stuart Weiss, an endocrinologist at NYU Langone Medical Center in New York. "We have to use our fortitude to resist overeating now that food is so available. And exercise is a great way to burn the extra energy created by the food we do eat."