We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

The Sweet Taste of Cannabinoids

Neuroskeptic iconNeuroskeptic
By Neuroskeptic
Jan 21, 2010 2:44 AMJun 27, 2023 7:33 PM


Sign up for our email newsletter for the latest science news

Every stoner knows about the munchies, the fondness for junk food that comes with smoking marijuana. Movies have been made about it.

It's not just that being on drugs makes you like eating: stimulants, like cocaine and amphetamine, decrease appetite. The munchies are something specific to marijuana. But why?

New research from a Japanese team reveals that marijuana directly affects the cells in the taste buds which detect sweet flavours - Endocannabinoids selectively enhance sweet taste.

Yoshida et al studied mice, and recorded the electrical signals from the chorda tympani (CT), which carries taste information from the tongue to the brain.

They found that injecting the mice with two chemicals, 2AG and AEA, markedly increased the strength of the signals produced in response to sweet tastes - such as sugar, or the sweetener saccharine. However, neither had any effect on the strength of the response to other flavours, like salty, bitter, or sour. Mice given endocannabinoids were also more eager to eat and drink sweet things, which confirms previous findings.

2-AG and AEA are both endocannabinoids, an important class of neurotransmitters. Marijuana's main active ingredient, ?9-THC, works by mimicking the action of endocannabinoids. Although ?9-THC wasn't tested in this study, it's extremely likely that it has the same effects as 2-AG and AEA.

In follow-up experiments, Yoshida et al found that endocannabinoids enhance sweet taste responses by acting on cannabinoid type 1 (CB1) receptors on the tongue's sweet taste cells themselves. In fact, over half of the sweet receptor cells expressed CB1 receptors!

This is an important finding, because CB1 receptors are already known to regulate the pleasurable response to sweet foods (amongst other things) in the brain. These new data don't challenge this, but suggest that CB1 also modulates the most basic aspects of sweet taste perception. The munchies are probably caused by ?9-THC acting at multiple levels of nervous system.

This paper also sheds light on CB1 antagonists. Given that drugs which activate CB1 make people eat more, it would make sense if CB1 blockers made people eat less, and therefore lose weight, a kind of anti-munchies effect. And indeed they do. Which is why rimonabant, a CB1 antagonist, was released onto the market in 2006 as a weight loss drug. It worked pretty well, although unfortunately it also it caused clinical depression in some people, so it was banned in Europe in 2008 and was never approved in the USA for the same reason.

The depression was almost certainly caused by antagonism at CB1 receptors in the brain, but Yoshida et al's findings suggest that a CB1 antagonist which didn't enter the brain, and only affected peripheral sites such as the taste buds, might be able to make people less fond of sweet foods without causing the same side-effects. Who knows - in a few years you might even be able to buy CB1 antagonist chewing gum to help you stick to your diet...

Yoshida, R., Ohkuri, T., Jyotaki, M., Yasuo, T., Horio, N., Yasumatsu, K., Sanematsu, K., Shigemura, N., Yamamoto, T., Margolskee, R., & Ninomiya, Y. (2009). Endocannabinoids selectively enhance sweet taste Proceedings of the National Academy of Sciences, 107 (2), 935-939 DOI: 10.1073/pnas.0912048107

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.