The CB1 cannabinoid receptor plays a role in how the tongue detects dietary fat | Research

The takeaway

Mice lacking CB1 cannabinoid receptors showed reduced preference for fatty foods, with impaired calcium signaling in taste bud cells and lower GLP-1 hormone levels.

Read this if you have noticed cannabis makes food taste better, especially fatty foods, and want to understand the science behind it.

CB1 receptor loss reduced fat taste preference and impaired taste bud signaling

What the researchers found

Researchers discovered that the CB1 cannabinoid receptor, the same receptor activated by THC, plays a previously unknown role in the tongue's ability to detect and prefer dietary fats.

Mice genetically engineered to lack CB1 receptors showed significantly lower preference for solutions containing rapeseed oil or the fatty acid linoleic acid compared to normal mice. Blocking CB1 receptors with rimonabant in normal mice produced the same reduction in fat preference.

The mechanism involved taste bud cells. While the fat-detecting receptors (CD36 and GPR120) were present at normal levels in CB1-deficient mice, the cells showed impaired calcium signaling in response to fatty acids. This means the cells could detect fat but could not properly translate that signal into a taste sensation.

Additionally, CB1-deficient mice had decreased levels of GLP-1, a hormone involved in satiety signaling, in their taste bud cells, suggesting the endocannabinoid system affects both fat taste perception and the hormonal response to dietary fat.

Why it matters

This study reveals a new mechanism through which the endocannabinoid system influences food intake: by modulating how the tongue perceives dietary fat. This helps explain why cannabis users often crave fatty foods ("the munchies") and why the CB1 blocker rimonabant reduced food intake in obesity trials. Understanding this taste-level mechanism could inform new approaches to managing obesity.

The numbers in context

CB1R knockout mice showed low preference for rapeseed oil and linoleic acid. Rimonabant administration produced similar fat preference reduction. No difference in CD36 or GPR120 protein levels. Impaired calcium signaling in CB1R knockout taste bud cells. Decreased proglucagon, GLP-1R mRNA, and GLP-1 basal levels in CB1R knockout mice.

How the study worked

Behavioral preference tests compared CB1R knockout mice and wild-type mice for fat-containing solutions. Rimonabant was used to pharmacologically block CB1R in normal mice. Taste bud cells were analyzed for protein expression (CD36, GPR120), calcium signaling responses to fatty acids, and GLP-1 mRNA and protein levels.

What this study cannot tell us

This is an animal study using knockout mice, which may not directly translate to human taste perception. The CB1R knockout affects the entire body, not just taste buds, making it difficult to isolate tongue-specific effects. The study used pure fatty acid solutions rather than complex foods. Human taste bud physiology may differ from mice.

How to read the evidence

This is a preclinical animal study using genetic knockout and pharmacological approaches, providing preliminary evidence for a new endocannabinoid mechanism.

When this study was published

Published in 2018. Research on the endocannabinoid system in taste perception continues.

The bigger picture

The "munchies" are one of the most recognizable effects of cannabis, but the mechanism has typically been attributed to brain-level appetite regulation. This study shows that the endocannabinoid system also operates at the very first step of food intake: taste perception on the tongue. This adds a peripheral mechanism to the central appetite effects of cannabinoids.

Questions still open

Does THC enhance fat taste perception in humans? Could targeting taste bud CB1 receptors provide appetite control without the psychiatric side effects of brain-penetrating CB1 blockers? Does chronic cannabis use alter fat taste sensitivity?

Common questions

Why does cannabis make food taste better?

This study found that CB1 cannabinoid receptors in the tongue help detect dietary fat. When these receptors are activated (as THC does), fat perception may be enhanced. When they are blocked or absent, preference for fatty foods decreases. This adds a taste-level mechanism to the brain-level appetite effects of cannabis.

Could this help treat obesity?

The CB1 blocker rimonabant reduced fat preference in this study, consistent with its weight-loss effects in humans (before it was withdrawn due to psychiatric side effects). Targeting CB1 receptors specifically in taste buds, rather than the brain, might provide appetite control without psychiatric risks.

Read the original research

Orosensory Detection of Dietary Fatty Acids Is Altered in CB₁R-/- Mice.

Nutrients, 10(10)

View on PubMed ↗Publisher’s paper ↗

Citation

Brissard, Léa; Leemput, Julia; Hichami, Aziz; Passilly-Degrace, Patricia; Maquart, Guillaume; Demizieux, Laurent; Degrace, Pascal; Khan, Naim Akhtar. (2018). Orosensory Detection of Dietary Fatty Acids Is Altered in CB₁R-/- Mice.. Nutrients, 10(10). https://doi.org/10.3390/nu10101347