Blocking CB1 cannabinoid receptors in the bed nucleus of the stria terminalis (BNST), a brain region involved in stress and anxiety, prevented opioid withdrawal-induced place aversion in rats.
Readers interested in how the endocannabinoid system relates to opioid withdrawal and addiction.
CB1 blockade in the BNST eliminated the emotional misery of opioid withdrawal in rats
What the researchers found
The bed nucleus of the stria terminalis (BNST) is part of the extended amygdala, a brain circuit involved in addiction, anxiety, and stress. Researchers investigated whether cannabinoid receptor modulation in this region could affect the aversive experience of opioid withdrawal.
In Experiment 1, infusing the CB1 antagonist AM251 directly into the BNST prevented naloxone-precipitated morphine withdrawal from producing conditioned place aversion (a measure of the unpleasant experience of withdrawal). This means blocking CB1 in the BNST eliminated the negative emotional component of opioid withdrawal.
In Experiment 2, infusing the MAGL inhibitor MJN110 (which boosts 2-AG) into the BNST did NOT prevent withdrawal aversion, unlike previous findings with MJN110 in other brain regions. This suggests different brain areas use different endocannabinoid mechanisms to process withdrawal distress.
Why it matters
The emotional distress of opioid withdrawal is a primary driver of relapse. Understanding exactly where and how the endocannabinoid system modulates withdrawal aversion could lead to targeted interventions that reduce the suffering of withdrawal without simply substituting one drug for another.
The numbers in context
AM251 in BNST: prevented withdrawal-induced place aversion. MJN110 in BNST: did not prevent aversion (unlike in other brain regions). Previous work showed AM251 also worked in central amygdala and MJN110 worked in basolateral amygdala and insular cortex.
How the study worked
Rats were made morphine-dependent, then withdrawal was precipitated with naloxone. Conditioned place aversion measured the aversive experience of withdrawal. CB1 antagonist (AM251) or MAGL inhibitor (MJN110) was microinjected directly into the BNST before conditioning trials.
What this study cannot tell us
Animal study using precipitated withdrawal, which is more acute than natural withdrawal. The BNST microinjection approach is not feasible in humans. The study measured conditioned place aversion, not all aspects of withdrawal. The specific mechanism by which CB1 blockade in the BNST reduces withdrawal aversion is not fully explained.
How to read the evidence
Preliminary evidence from a single animal study with region-specific brain manipulations.
When this study was published
Published in 2017. Preclinical research on endocannabinoid-opioid interactions.
The bigger picture
This study maps the endocannabinoid-opioid interaction at the level of specific brain nuclei. The picture emerging is that CB1 receptor blockade reduces withdrawal distress through multiple connected brain regions (BNST, central amygdala), while 2-AG boosting works through different areas (basolateral amygdala, insular cortex). This regional specificity could inform more targeted therapeutic approaches.
Questions still open
- Why does CB1 blockade reduce withdrawal aversion in the BNST but 2-AG enhancement does not? Could systemic CB1 modulation be used to ease opioid withdrawal in clinical settings? What is the optimal endocannabinoid manipulation strategy across all withdrawal-relevant brain regions?
Common questions
Could targeting cannabinoid receptors help with opioid withdrawal?
Does cannabis help with opioid withdrawal?
Read the original research
CB₁ receptor antagonism in the bed nucleus of the stria terminalis interferes with affective opioid withdrawal in rats.
Behavioral neuroscience, 131(4), 304-11
Citation
Wills, Kiri L; DeVuono, Marieka V; Limebeer, Cheryl L; Vemuri, Kiran; Makriyannis, Alexandros; Parker, Linda A. (2017). CB₁ receptor antagonism in the bed nucleus of the stria terminalis interferes with affective opioid withdrawal in rats.. Behavioral neuroscience, 131(4), 304-11. https://doi.org/10.1037/bne0000201
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