It’s a well-known fact that using cannabis often leads to the “munchies,” prompting consumers to eat more and crave tasty, high-calorie foods. Now, a new study published in the journal Current Biology has found that cannabinoids can give worms the munchies, too — specifically, nematodes (C. elegans).
“Cannabinoids make nematodes hungrier for their favored foods and less hungry for their non-favored foods,” said study co-author Shawn Lockery in a news release. “Thus, the effects of cannabinoids in nematodes parallels the effects of marijuana on human appetites.”
Lockery added that nematodes diverged from the lineage leading to mammals more than 500 million years ago, calling it “truly remarkable” that cannabinoids’ effects on appetite have been preserved through this amount of evolutionary time.
The study was originally inspired by Oregon’s legalization of cannabis in 2015. Lockery said their lab was examining nematode food preferences, relating to research on the neuronal basis of economic decision-making, when they decided to investigate whether cannabinoids would alter their preferences.
Nematodes also look a lot more like people at the molecular level than many other species, researchers note, begging the question if the feeding effects of cannabinoids would persist across species.
Cannabinoids bind to cannabinoid receptor proteins in the brain, nervous system and other parts of the body, researchers explain. These receptors respond to endocannabinoids, which are molecules already in the body. The endocannabinoid system is known to play a crucial role in a number of bodily functions, like eating, learning, memory, reproduction and more.
Researchers demonstrated that worms exposed to anandamide, an endocannabinoid, ate more of their favorite food, with effects dependent on the presence of the worms’ cannabinoid receptors.
Further studies had researchers genetically replace the nematode cannabinoid receptor with the human cannabinoid receptor, finding that animals responded normally to cannabinoids. Researchers said this discovery emphasized the commonality of cannabinoid effects in nematodes and humans, adding that the effects of anandamide depend on neurons that play a role in food detection.
The study concluded, “In mammals, administration of THC or endocannabinoids induces hedonic feeding,” specifically citing that anandamide was shown to alter food consumption and “differentially alter appetitive behavior.”
Lockery elaborated, explaining that the sensitivity of one of the main food-detecting olfactory neurons in nematodes is “dramatically altered” by cannabinoids. He explained that, once exposed to cannabinoids, the worm becomes more sensitive to favored food odors and less sensitive to non-favored odors.
“This effect helps explain changes in the worm’s consumption of food, and it is reminiscent of how THC makes tasty food even tastier in humans,” Lockery said.
Of course, it’s simply fun to know that worms can have a similar experience to a human chowing down on a bag of Cheetos after smoking a blunt, but Lockery explained how these findings have meaningful, practical applications.
“Cannabinoid signaling is present in the majority of tissues in our body,” he said. “It therefore could be involved in the cause and treatment of a wide range of diseases. The fact that the human cannabinoid receptor gene is functional in C. elegans food-choice experiments sets the stage for rapid and inexpensive screening for drugs that target a wide variety of proteins involved in cannabinoid signaling and metabolism, with profound implications for human health.”
There are still a number of outstanding questions to explore on this issue, namely how cannabinoids change the sensitivity of nematodes’ olfactory neurons, which don’t have cannabinoid receptors. Researchers were also curious to study how psychedelics interact with nematodes in the future.