Alcohol-Seeking Behavior May Increase After Stroke

Numerous studies show a link between excessive alcohol intake and stroke. While alcohol can increase the risk of stroke and other adverse health events, many Americans continue to consume it.

A new study published by Scientific Reports suggests that certain types of strokes can increase alcohol-seeking behavior in animals. Importantly, if confirmed in humans, this behavior may lead to a recurrent stroke.

“It’s important because although stroke is a severe disease, more and more people are surviving and recovering after their first stroke,” said co-principal investigator Jun Wang, MD, PhD. “Therefore, it is important to study behavior change after stroke, and how that behavior can affect the chances of having another one, which is often fatal.”

After a first stroke, healthcare providers urge patients to limit alcohol intake to prevent recurrent strokes. This recommendation may be difficult to follow if a part of the brain that was damaged during the stroke may amp up desire for alcohol.

“In an ischemic stroke, a blood vessel to the brain is blocked, which deprives the neurons in the brain of glucose and oxygen,” said co-principal investigator Farida Sohrabji. “Neurons are very dependent on these 2 nutrients, and without them, neurons very rapidly begin to die.”

The authors found that after an ischemic stroke in the middle cerebral artery, animal models had lower overall fluid intake; however, the animals showed a preference for alcohol over water, according to the study.

Even though the stroke affected only 1 side of the brain and left the other side undamaged, the authors said the results were significant.

“Their preference for alcohol can be seen 5 days after stroke and through at least the first month after the stroke,” Wang said. “Specifically, when given a choice between water and alcohol, they chose alcohol a higher percentage of the time than they did before the stroke.”

The investigators hypothesize that during the stroke, neurons in the dorsal lateral striatum are killed and they stop inhibiting neurons in the midbrain, according to the study.

Without the dorsal lateral striatum, the midbrain neurons are more excitable and send signals to D1 dopamine receptors. The investigators have previously shown that D1 receptor-containing cells compel individuals to carry out an action, such as drinking alcohol.

“This circuit is interesting because it means that when the dorsal lateral striatum neurons die, the result is increased excitement of the D1 neurons in the dorsomedial striatum,” Dr Wang said. “It is this increased excitement that we think is causing alcohol-seeking behavior.”

Interestingly, when the D1 receptor was blocked, alcohol-seeking behavior was diminished, while the control group remained unchanged, according to the study.

“This is a hint at how the brain works,” Dr Wang said, “and although we’re a long way off, something to inhibit this D1 receptor might be a possible therapeutic target for a drug to help people resist the urge to drink after a stroke.”

While additional studies are needed to explore the potential link in humans, these findings suggest that ischemic stroke in the middle cerebral artery — a common type of stroke – could increase the risk of recurrent events.

“As much as possible, we tried to use a model that would replicate the experience of a human patient,” Dr Sohrabji concluded. “Therefore, we think that these findings, although preliminary, might eventually help people who have experienced any type of brain injury, whether a stroke or an accident that causes traumatic brain injury."