Assorted liquor bottles on a table: Image credit: John Cafazza (CC0)
Stress and addiction are closely connected. Chronic stress can make the brain more sensitive to drugs and alcohol, increasing the risk of addiction. A key brain region involved in stress responses is the extended amygdala, which communicates with other areas responsible for decision-making and habit formation.
Within this system, the chemical messenger CRF triggers stress responses. Cholinergic interneurons, a specific type of neuron in the striatum, help balance brain activity and regulate motivation and behavior. These neurons also control dopamine, a chemical messenger essential for learning and reward. Although alcohol interacts with stress systems, its effects on communication between stress-related brain regions and the striatum remain poorly understood. Understanding how stress signals affect cholinergic interneurons could provide insight into addiction and other mental health conditions.
Essoh et al. aimed to investigate how alcohol influences stress signals from the extended amygdala to cholinergic interneurons in the dorsal striatum of mice and rats. Using mouse brain slices, they found that CRF released from extended amygdala inputs exerts an excitatory effect on cholinergic interneurons in the dorsal striatum. These neurons play a key role in learning and goal-directed behavior. However, alcohol significantly reduced this CRF-induced excitation.
This effect appears to result from local actions within the striatum, involving inhibition of synaptic transmission. These findings suggest that alcohol suppresses stress-related communication in brain circuits governing motivation and habit formation, which may impair the brain’s ability to adapt to changing environments and promote compulsive or habitual alcohol consumption.
These insights could inform treatments for addiction and stress-related psychiatric disorders. By understanding how alcohol disrupts stress circuits, it may be possible to develop interventions that restore healthy connectivity between brain regions involved in motivation and behavioral control. Future studies in live animals are needed to confirm these effects and assess whether they produce long-term behavioral changes, particularly those associated with compulsive drug use.
