Methamphetamine Brain Damage Increased Endocannabinoid Levels and Alcohol Drinking in Mice
Meth-induced brain damage raised 2-AG endocannabinoid levels in the limbic forebrain and increased alcohol consumption in mice, effects that were blocked by a CB1 receptor antagonist.
Quick Facts
What This Study Found
Mice exposed to a neurotoxic methamphetamine regimen showed increased alcohol consumption and preference seven days later.
Biochemical analysis of the limbic forebrain revealed that while CB1 receptor density and activity were unchanged, 2-AG (endocannabinoid) levels were significantly elevated. This increase was associated with reduced MAGL (the enzyme that breaks down 2-AG) activity.
As expected, dopamine levels and dopamine transporter density were decreased (reflecting meth neurotoxicity).
The CB1 receptor antagonist AM251 prevented the meth-induced increase in alcohol consumption. Conversely, a MAGL inhibitor (which raises 2-AG) increased alcohol consumption in both meth-treated and control mice.
This suggested that increased endocannabinoid tone following meth neurotoxicity drives increased alcohol seeking.
Key Numbers
Meth: 4 mg/kg x 4 doses. 7 days later: increased 2-AG, decreased MAGL activity, decreased dopamine, decreased dopamine transporters. CB1 receptor density/activity unchanged. AM251 blocked increased drinking. MAGL inhibitor increased drinking.
How They Did This
Mice received neurotoxic methamphetamine (4 mg/kg x 4, 2 hours apart) and were tested for alcohol consumption 7 days later with increasing ethanol concentrations (3-20%). Limbic forebrain was analyzed for CB1 density/activity, 2-AG levels, MAGL activity, dopamine levels, and dopamine transporter density. CB1 antagonist and MAGL inhibitor were tested for effects on drinking.
Why This Research Matters
This study identified an endocannabinoid mechanism linking methamphetamine neurotoxicity to increased alcohol consumption, suggesting that meth use could change brain chemistry in ways that promote polysubstance use.
The Bigger Picture
Polysubstance use is common but poorly understood mechanistically. This study provided a concrete biological pathway through which damage from one drug (meth) could increase use of another (alcohol) via the endocannabinoid system.
What This Study Doesn't Tell Us
Animal model using a specific neurotoxic meth protocol. Human meth use patterns differ. The 7-day timepoint may not reflect longer-term changes. Alcohol preference in mice may not directly model human alcohol-seeking behavior.
Questions This Raises
- ?Could endocannabinoid system modulation reduce alcohol craving in meth users?
- ?Does this mechanism apply to cannabis co-use as well?
- ?Would FAAH inhibition have different effects than MAGL inhibition on alcohol drinking?
Trust & Context
- Key Stat:
- Meth damage increased endocannabinoid 2-AG levels and alcohol drinking; CB1 blocker prevented this
- Evidence Grade:
- Preclinical study with pharmacological confirmation of the mechanism. Limited to animal models and a specific meth protocol.
- Study Age:
- Published in 2010. The role of the endocannabinoid system in polysubstance use has continued to be investigated.
- Original Title:
- Involvement of 2-arachidonoyl glycerol in the increased consumption of and preference for ethanol of mice treated with neurotoxic doses of methamphetamine.
- Published In:
- British journal of pharmacology, 160(3), 772-83 (2010)
- Authors:
- Gutierrez-Lopez, M D, Llopis, N, Feng, S(2), Barrett, D A, O'Shea, E, Colado, M I
- Database ID:
- RTHC-00417
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why would meth damage increase alcohol drinking?
Meth damages dopamine neurons, creating a low-dopamine state. The brain may compensate by increasing endocannabinoid (2-AG) signaling, which promotes reward-seeking behavior including alcohol consumption.
Could this mechanism apply to humans?
The link between meth use and increased alcohol problems has been observed in humans, and the endocannabinoid mechanism identified here is plausible. However, human polysubstance use involves many additional psychological and social factors beyond this specific biological pathway.
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Cite This Study
https://rethinkthc.com/research/RTHC-00417APA
Gutierrez-Lopez, M D; Llopis, N; Feng, S; Barrett, D A; O'Shea, E; Colado, M I. (2010). Involvement of 2-arachidonoyl glycerol in the increased consumption of and preference for ethanol of mice treated with neurotoxic doses of methamphetamine.. British journal of pharmacology, 160(3), 772-83. https://doi.org/10.1111/j.1476-5381.2010.00720.x
MLA
Gutierrez-Lopez, M D, et al. "Involvement of 2-arachidonoyl glycerol in the increased consumption of and preference for ethanol of mice treated with neurotoxic doses of methamphetamine.." British journal of pharmacology, 2010. https://doi.org/10.1111/j.1476-5381.2010.00720.x
RethinkTHC
RethinkTHC Research Database. "Involvement of 2-arachidonoyl glycerol in the increased cons..." RTHC-00417. Retrieved from https://rethinkthc.com/research/gutierrez-lopez-2010-involvement-of-2arachidonoyl-glycerol
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.