image: This working model shows how chronic exposure to the psychoactive component of marijuana may increase dopamine levels by altering the function of an inhibitory cell type, contributing to the drug's pleasurable and potentially addictive qualities. view more
Credit: Friend et al., <i>JNeurosci</i> (2017)
Cellular-level changes to a part of the brain's reward system induced by chronic exposure to the psychoactive component of marijuana may contribute to the drug's pleasurable and potentially addictive qualities, suggests a study in young mice published in JNeurosci. The results could advance our understanding of marijuana's effects on the developing brain as the drug's rapidly changing legal status increases its recreational and medical use in the United States.
Drugs of abuse impact the ventral tegmental area (VTA) of the brain, which is rich in dopamine neurons. Using juvenile and adolescent mice, Jeffrey Edwards and colleagues investigated the effects of tetrahydrocannabinol (THC), the chemical in marijuana responsible for its effects on cognition and behavior, on VTA GABA cells, an understudied inhibitory cell type in the reward system that regulates dopamine levels.
The authors found that a week of daily THC injections, but not a single injection, blocked the recovery of synapses onto VTA GABA cells in the mice. This finding suggests that persistent THC may alter the inhibitory function of these cells, increasing dopamine levels and the rewarding features of marijuana. These GABA neurons may represent a promising new target for treatment of cannabis use disorder, a common condition on the rise in the United States.
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Article: CB1-Dependent LTD in Ventral Tegmental Area GABA Neurons: a Novel Target for Marijuana DOI: https://doi.org/10.1523/JNEUROSCI.0190-17.2017 Corresponding author: Jeffrey Edwards (Brigham Young University, Provo, Utah, USA), Jeffrey_Edwards@byu.edu
About JNeurosci
JNeurosci, the Society for Neuroscience's first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.
About The Society for Neuroscience
The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.