THC Can Reduce Sociability in Mice, Study Finds
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While cannabis is often associated with social settings, new research has found that exposure to the drug can increase social isolation – at least, in mice.
Published in Nature, the study found that, when injected with THC, the mice became less sociable with their fellow rodents. This effect could be reversed, however, with a separate injection of lactate – a natural byproduct of respiration.
The researchers say the study is the first to show a decline in sociability from cannabis consumption as a result of altered glucose metabolism in the brain.
To make their findings, the researchers studied the cannabinoid receptors (CB1) located along the mitochondria within star-shaped nerve cells called astrocytes.
Undisrupted, these cannabinoid receptors help the mitochondria to produce lactate as part of the respiration process. This lactate is then used as a kind of fuel for other neurons linked to social behavior.
But when these cannabinoid receptors are plugged by THC, the researchers say, less lactate is produced, which in turn reduces social interactions.
To test the effects of blocking this cannabinoid receptor, Marsicano and his colleagues injected mice with 10 milligrams per kilogram of THC and studied the effects over 24 hours. They observed that the drug
“Social interactions were studied by different tests, recording the time spent by mice exploring a congener,” Dr Giovanni Marsicano, an author of the study and researcher at Université Bordeaux, told Analytical Cannabis.
These incidences of social isolation disappeared, however, when the mice’s lactate levels were artificially topped up with lactate injections.
“We do not know the exact nature of the neurons affected,” Marsicano added. “We know that they are in the hippocampus and prefrontal cortex – brain regions involved in the control of social behavior.”
Marsicano says the findings could one day further research into new therapeutic solutions for behavioral problems associated with cannabis exposure. But, in the meantime, the results clarify the intricate relationships between certain biological molecules and brain behaviors.
“This paper is important because it shows the tight link between energy management in the brain and behavior,” he told Analytical Cannabis. “CB1 receptors are key regulators of these processes.”