Brain Cells Link Hunger to Alcohol Cravings in New Study
Hunger activates fight-or-flight neurons in the brain that influence whether alcohol is remembered as rewarding, according to a study published in Current Biology. Researchers at Brown University mapped and isolated hunger-responsive neurons in the common fruit fly to uncover how internal states shape the formation of addiction-related memories.
Mapping Neural Circuits in Fruit Flies
The research team at Brown’s Carney Institute for Brain Science used the common fruit fly as a model for observing neural behavior because of its sophisticated brain structure. The investigation focused on how food-deprived organisms process environmental cues related to substances. Previous studies from the lab of Karla Kaun, an associate professor of neuroscience at Brown, examined how memories of alcohol act as rewards to drive cravings, primarily focusing on dopamine. For this study, the scientists investigated octopamine, a fly neurotransmitter equivalent to human norepinephrine that responds to hunger, thirst, and pain.
Silencing Neurons Alters Alcohol Preference
The researchers observed that genetically silencing or activating a single octopamine neuron in the brain, designated as VUMa3, affected how quickly flies found alcohol rewarding. This genetic manipulation altered alcohol preference exclusively when the flies were hungry. Kaun explained that hunger recruits new neurons to communicate with brain circuits that connect environmental cues with the rewarding sensations of alcohol. For instance, a person who regularly passes a favorite bar might ignore a sign on the way home after a normal lunch, but skipping a meal and feeling hungry can make that same sign trigger an alcohol craving.
Implications for Human Addiction and Relapse
Lewis Sherer, a postdoctoral researcher at Brown and the study’s first author, noted that understanding how simpler organisms remember alcohol provides insight into how humans associate environmental cues with drinking. This mechanism offers potential hints for preventing relapse and treating addiction. The findings suggest that external stressors like food insecurity influence internal reward systems. Sherer stated that living through conditions of severe hunger or stress can increase a person’s propensity to develop an alcohol addiction. Funding for the research was provided by the National Institute on Alcohol Abuse and Alcoholism, the National Institute of Neurological Disorders and Stroke, the National Institute of General Medical Sciences, the National Institute on Aging, the National Institute on Deafness and Other Communication Disorders, the Hubert & Richard Hanlon Trust, the Howard Hughes Medical Institute, and the Carney Institute.
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