Sharing Your Stash With Your Rat Will Ease Its Nausea

Link proven between nausea and the brain receptor for cannabinoids, in rats, which could be good news for human chemotherapy patients one day

A rat sits on the ledge of a Times Square subway platform in New York
Richard Drew/AP

If your rat has a tendency to vomit, sharing your marijuana with it will help, one may infer from a paper Canadian scientists published Monday in the eNeuro, a journal of the Society for Neuroscience. Right now this is good news mainly for pot-heads with pets, but the researchers hope their discoveries will one day help cancer patients taking stomach-turning chemotherapy too.

Cannabidiol, the form of marijuana without the fun psychotropic components, could potentially be developed into anti-nausea treatments, explain Dr. Linda Parker and colleagues of the University of Guelph, who gained new insights on how exactly the marijuana is connected with nausea.

After rats were injected with a chemical to make them sick to their stomachs, the level of the neurotransmitter serotonin surged in their brain region responsible for nausea, the researchers observed. The rats also demonstrated "gaping" - behavior typical of nauseated rodents, showing they really did feel terrible. 

But if the rats were dosed with cannabidiol before being injected with the sickening lithium chloride, they did not gape, and the serotonin level in their interoceptive insular cortexes did not increase.

Ergo, giving them the marijuana derivative before administering nauseating injections kept them feeling okay.

Meanwhile, artificially elevating the concentration of a biochemical that our bodies produce called 2-AG, a sort of "endogenous cannabinoid," also prevented serotonin from increasing in the rats' cortexes.

The active chemical in pot, and our own 2-AG, both trigger a receptor in our brains and nervous systems, called the cannabinoid type 1 receptor. So this receptor seems linked to nausea, at least in Rattus norvegicus.

Therefore, one day, this rat study could lead to new therapeutic opportunities, and meanwhile, if your rat starts throwing up, you know what to do.