Mice Will Eat THC Edibles, But Not If They’re Potent, Finds Study
New research has found that mice will repeatedly choose to consume a dough mixture containing the psychoactive tetrahydrocannabinol (THC) but are less willing to eat highly potent edibles.
The new study, published in the journal Drug and Alcohol Dependence last month, is among the first to report the voluntary oral consumption of THC in animals.
The authors noted that consumption generally led to the mice becoming less active, though this effect did vary based on the sex of the mice.
Evaluating the safety of edibles
The popularity of edibles as a method of cannabis consumption has grown significantly in recent years. In 2016 only 2.5 percent of US participants in the Global Drug Survey reported edibles as their most frequently chosen consumption method, but just two years later this figure had grown more than five-fold to 13.7 percent.
“People can buy cookies, candies and all sorts of things with THC in them. Back in the day, you had to make your own brownies, or something like that, and now they are becoming more widely available and increasing in popularity,” said Michael Smoker, the first author of the paper and an addiction neuroscience PhD candidate at Indiana University: Purdue University Indianapolis, in a press statement.
Cannabis edibles can elicit extreme adverse reactions in some people, said Smoker. This is often because people are unsure about the exact volume of cannabis edible that they should be consuming to reach their desired level of intoxication, and often end up eating more than they should.
Evaluating the safety of cannabis edibles use in humans can get very complicated, very quickly; there are several ethical concerns associated with using people in drug trials and researchers also can’t control a subject’s prior exposure to THC or other drugs. As a result, researchers have started turning to mice models in order to study the effects of cannabis.
But until now, Smoker says, there had been difficulties in figuring out a way to get the mice to self-administer the drug. In the past, studies on mice models would simply inject the mice with the drug, but to more accurately reflect the human consumption of edibles, the researchers here set out to develop a new, edible model of THC administration for mice.
Reaction to the new mouse edibles
The researchers created a palatable dough for the mice, which was made from flour, sugar, salt, glycerol, and some gradually increasing amount of THC. The dosage of THC included in the dough varied from 1 to 10 mg/kg.
They observed that the dough was generally well-consumed by the mice, but that there was a drop-off in consumption towards the stronger THC concentrations. Importantly, the mice appeared to eat the dough voluntarily, and were also choosing to return to it.
While the mice were less willing to eat the more potent dough, the THC dosage in the more palatable doughs was still enough to elicit noticeable changes to their behavior. After consuming some of the dough, the mice became less active and there was a noticeable drop in their body temperatures. Interestingly, these effects were also sex-dependent, with males experiencing more pronounced changes, as well as dose-dependent for both sexes.
“In contrast to other cannabinoid self-administration models, edible THC is relatively low in stress and uses a route of administration analogous to one used by humans,” wrote the researchers in the published report. They believe that their self-administration model could open the door to further mouse model studies of orally consumed cannabis, which in turn could lead to a better understanding of the behavioral and physiological effects associated with cannabis use.