It’s well known that under the influence of marijuana, the urge to snack increases. New research sheds further light on as to why.
Previous research out of Washington State University in 2018 zeroed in on the cannabis munchies mystery. Exposure to tetrahydrocannabinol (THC), an intoxicating cannabinoid, was found to trigger a surge of a compound secreted primarily in the lining of the stomach – the hormone acyl-ghrelin (AG), known as the “hunger hormone”.
Cannabis also changed the activity of brain cells in the hypothalamus, which responded to this hormone. The main role of the hypothalamus, which is located in the ventral brain above the pituitary gland and below the third ventricle, is to keep the body in “homeostasis” – meaning a healthy and balanced internal state. This includes controlling body temperature and hunger.
In the new study, researchers used calcium imaging technology, similar to a brain MRI, to determine how the brain cells of exposing mice to vaporized cannabis sativa responded. Exposure to cannabis vapor produced a transient, significant increase in food intake two and three hours after exposure. Further analysis of meal patterns revealed cannabis vapor exposure increased meal frequency, but reduced meal size throughout the evaluation period.
So, what was happening in the brains of these animals?
“When the mice are given cannabis, neurons come on that typically are not active,” said Jon Davis, an assistant professor of neuroscience at WSU and an author of the paper. “There is something important happening in the hypothalamus after vapor cannabis.”
The cannabinoid-1 receptor (CB1), which is a known cannabis target, controlled the activity of a “feeding” cells in the hypothalamus, called Agouti Related Protein neurons. When these neurons were switched off, cannabis no longer promoted appetite.
Why is this research important?
The WSU study could be important in the development of refined therapeutics to treat disorders affecting appetite experienced by cancer patients, as well as anorexia and potentially obesity.
This was the first known study to use calcium imaging to understand the effect on hunger following cannabis exposure. The discovery has been detailed in the journal Scientific Reports.