As many people will be aware, going out for “just one drink” can easily become two, three, or four. While that’s all well and good for most of us, this type of escalation can ruin the lives of alcoholics who just can’t seem to stop drinking once they start. Fortunately, however, researchers may have now identified the neurons responsible for this lack of restraint, and could have figured out a way to alter their activity.
Writing in the journal Biological Psychiatry, the scientists explain that many of our urges and behaviors are controlled by brain cells called medium spiny neurons (MSNs), each of which has one of two types of dopamine receptor, known as D1 and D2 receptors. D1 neurons form part of the so-called “go” pathway, as when they are activated they tend to stimulate us into action. Conversely, D2 neurons make up the “no-go” pathway, and when activated cause us to refrain from doing certain things.
The activity of these two types of MSN is controlled by a number of different neurotransmitters. Among these are glutamate, which increases neurons’ activity, and GABA, which decreases their activity.
During their research, the study authors fed alcohol to lab mice over a period of time, essentially making them alcoholic. They then analyzed the MSNs in a brain region called the dorsomedial striatum (DSM), which has previously been shown to play a major role in drug and alcohol addiction.
Interestingly, they found that becoming alcoholic altered the plasticity of these neurons, meaning their receptiveness to certain neurotransmitters changed. More specifically, the “go” neurons became increasingly sensitive to glutamate while the “no-go” MSNs became more sensitive to GABA. As a consequence, the “go” pathway is activated while the “no-go” pathway is deactivated, ultimately causing the mice to continue drinking.
However, the researchers were able to chemically block the transmission of GABA in “no-go” neurons in the rodents’ DSMs, increasing their activity and causing the alcoholic rodents to stop drinking. Based on this discovery, the study authors believe similar mechanisms may underlie the uncontrolled drinking of some people, suggesting that if the “no-go” neurons in key brain regions of alcoholics can be activated then they may be able to break their habits.
Though more work is needed before this technique can be applied to humans, study co-author Jun Wang is feeling positive about the potential implications of this research, saying: “I hope these findings will eventually be able to be used for treatment for alcohol addiction.”
Image: Neurotransmitters like GABA and glutamate affect the activity of both "go" and "no-go" neurons. adike/Shutterstock