How cannabis can affect appetite through brain changes

New research on cannabis sheds more light on how it alters eating habits and how it leads treatments for appetite loss in certain illnesses.

The study, published by Washington State University in the Society for the Study of Ingestive Behavior, uses new procedures to dose lab rats with cannabis vapor, revealing how the drug triggers hunger hormones.

Scientists also identified brain regions that shift to the hunger state while under the influence.

“We all know cannabis use affects appetite, but until recently we’ve actually understood very little about how or why,” explained Jon Davis, Ph.D., researcher in the Department of Integrative Physiology and Neurosciences at Washington State.

“By studying exposure to cannabis plant matter, the most widely consumed form, we’re finding genetic and physiological events in the body that allow cannabis to turn eating behavior on or off.”

Tetrahydrocannabinol (THC), the psychoactive component of cannabis, is the cannabinoid that is mainly responsible for appetite stimulation. This can be used to treat many illnesses that cause extreme appetite loss.

Researchers had developed a vapor exposure system for this study to copy how often people consume cannabis. This allowed for a control of dosage while the rats’ meals were monitored over the course of the day.

Brief exposure to cannabis vapor stimulated a meal even when rats had recently eaten, suggesting that inhaling cannabis tricks appetite circuits in the brain into hunger mode.

“We found that cannabis exposure caused more frequent, small meals,” stated Davis. “But there’s a delay before it takes effect.”

That delay provided a clue to how the drug may act. Usually, when the stomach is empty it releases a hormone called ghrelin which sends a message to the brain that it’s time for food. The researchers found that the cannabis triggered a ghrelin surge.

When the researchers gave a second drug which prevented the ghrelin surge, cannabis no longer triggered appetite stimulation. They also found changes in how the brain responds to the message.

In small region of the hypothalamus responsible for sensing ghrelin, cannabis changed the genetic activity of brain cells that respond to the hormone.

The researchers believe that deciphering the ways cannabis acts in the body to alter appetite can lead to new treatments for illness-induced anorexia.

It is important to note that cannabis is used currently to treat poor appetite and illnesses like anorexia nervosa and bulimia.

Severe appetite loss is a common symptom of many chronic illnesses, and is especially problematic in cancer, HIV/AIDS, heart disease, and some metabolic disorders.

A targeted treatment that offers the beneficial effects on appetite without the broader effects on the mind and body could increase quality of life and speed recovery.