Science Explains The Munchies
Whether or not you’ve used marijuana, you probably know (or have heard) that there’s an uncontrollable urge to nosh on everything in sight that follows use of the drug — a phenomenon known as the “munchies.”
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Now — finally! — we have a better understanding of why cannabis-users can’t seem to stop eating. According to a new study from researchers at Yale School of Medicine, this bottomless hunger seems to be the result of brain cells that normally make the body feel full. But, when under the influence of marijuana, these same neurons make people hungry instead.
For the study, just-published in the journal Nature, scientists looked at what happens to neuron activity as cannabis works on the brains of mice, by manipulating some of the cellular pathways that respond to marijuana use. Specifically, they wanted to see how the neurons that promote fullness respond to the cannabis, with the idea that they should be shut off, knowing marijuana’s reputation for promoting hunger.
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However, the researchers were surprised to find the exact opposite was true: these pro-opiomelanocortin (POMC) neurons that normally promote that feeling of fullness were activated with the cannabis, yet promoted a hungry feeling instead. (Whaaat?)
Perplexed, the scientists tinkered around a little more. Ultimately they found that, when they selectively turned off the neurons, marijuana-triggered urges to eat died down significantly. When they boosted the activity in these neurons, they saw an even stronger urge to snack.
Lead author Tamas Horvath, a professor of neurobiology and director of the Cell Signaling and Neurobiology of Metabolism at Yale University School of Medicine, says that he and his colleagues concluded that these neurons were actually mediators of the marijuana-induced munchies, not just found to promote satiety.
“In the past 17 years, it was assumed that the main role of these POMC neurons is to suppress appetite and eating,”he tells Yahoo Health. “We show now that they can induce eating, as well, under certain circumstances.”
How does that work exactly? The researchers weren’t sure at first. “We then asked, ‘How is it possible that a neuron, that at one moment suppresses feeding, becomes the driver of feeding the next?’”Horvath says. “It’s because the neurons switched the chemicals that they released.”
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Marijuana seems to spark the release of opioids called beta-endorphin, says Horvath. This then seems to act on receptors that promote eating behavior, in essence, changing the function of the cells. So, as for the “munchies,”now you know.
But beyond explaining that phenomenon, there could easily be a wider use for this research, according to Horvath. First, the scientists want to better understanding if these neurons also contribute to the “high”seen with cannabis. Second, they’d like to gain a better grasp on how those rapid shifts in neuron function work.
Lastly and importantly, this research may also be a first step in helping to ease problems associated with tough medical treatments. “There are medical conditions, such as cancer cachexia, where people have no appetite, in part because overactivity in the POMC neurons suppress eating,”he explains. “Perhaps targeting these neurons specifically with new compounds could be more effective in reversing cachexia than the medications that are currently available.”
One place the urge to eat would be hugely beneficial.
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