Cannabis compound could kill nausea during chemo without high: Guelph study

Researchers at the University of Guelph and the University of Calgary have found a non-psychoactive compound in cannabis that can curb nausea in rats.

THC in cannabis is already used to ease nausea and vomiting

A new study from researchers at the University of Guelph and University of Calgary has found a non-psychoactive compound in cannabis can help curb nausea. (Kirsten Murphy/CBC)

A cannabis compound that won't get users high can help ease the nausea cancer patients experience when going through chemotherapy, a new University of Guelph study suggests.

One of the first medical uses of THC (tetrahydrocannabionl), the psychoactive compound in cannabis that results in a person becoming high, was to treat chemotherapy-induced nausea and vomiting.

This study shows alternate compounds of the cannabis plant could be used and are just as, or more effective, than other drugs used for nausea.

"We know a lot about the neurobiology of vomiting and how to control vomiting with anti-emetic drugs. However, nausea's much more difficult to control with these drugs. And it persists," said Linda Parker, a psychology professor at Guelph who was part of a team of researchers that included lead author Cheryl Limebeer, Erin Rock and University of Calgary physiology and pharmacology professor Keith Sharkey.

"Finding new treatments for nausea is really critical in the quality of life of chemotherapy patients," Parker said.

Treatments could 'turn off' nausea triggers

For the study, researchers looked at rats.

Rats cannot vomit, but they can display a "disgust" reaction called gaping, which happens when they're re-exposed to something they've eaten previously that made them feel sick.

Like humans, the interoceptive insular cortex is the part of a rat's brain responsible for nausea. When serotonin releases in that part of the brain, people and rats feel nauseous.

In their research, the Guelph and Calgary scientists gave the rats cannabidiol, a non-psychoactive compound found in cannabis. Then they gave the same rats a drug to produce nausea.

The results showed the cannabidiol prevented a spike of serotonin in that part of the brain and stopped the rats from gaping.

The researchers also found using a drug to boost the natural cannabinoid called 2-AG (2 arachidonoyl glycerol), which is already in the brain, also eased feelings of nausea.

"If we can elevate this natural canavoid that the brain produces, we can treat nausea in the future," Parker said.

In humans, she added, "These treatments, presumably, would reduce the elevation of serotonin that triggers nausea and turn it off."

The research, which appeared in the journal eNeuro this week, is pre-clinical.

Parker said the research team is hopeful a clinical researcher will carry the study on to the next step of human trials to see how it could help cancer patients.