Cannabis and sociability: glucose metabolism implicated

A recent study by Inserm in collaboration with the Spanish University of Salamanca shows that exposure to cannabis alters glucose metabolism in the brain, leading to behavioral changes linked to sociability. From cannabinoid receptors located in star-shaped cells of the central nervous system called astrocytes, are thought to be at the origin of this relationship.

The study, published in Nature follows the 2012 discovery of endocannabinoid receptors located on the membrane of mitochondria, the intracellular organelles whose role is to provide cells with the energy they need.

Among other functions, these cells play a very important role in the brain's energy metabolism.

«Given the importance of astrocytes and energy utilization for brain function, we wanted to understand the role of these very specific cannabinoid receptors, and the consequences for the brain and behavior when exposed to cannabis.», explains Giovanni Marsicano.

The researchers then gave THC to mice, and observed that persistent activation of mitochondrial cannabinoid receptors in astrocytes triggered a cascade of molecular processes leading to dysfunctional glucose metabolism in astrocytes.

This reduced the capacity of astrocytes to convert glucose into «food» for neurons. In the absence of additional energy intake, neuronal function was compromised in the animals, with a detrimental impact on behavior. In particular, social interaction decreased for up to 24 hours after THC exposure.

«Our study is the first to show that the reduced sociability sometimes associated with cannabis use is the result of altered glucose metabolism in the brain. It also opens up new avenues of research to find therapeutic solutions to alleviate some of the behavioral problems resulting from cannabis exposure. In addition, it reveals the direct impact of astrocyte energy metabolism on behavior«, explains Marsicano.