April 24, 2023 -- Research on mice led scientists to conclude that chronic alcohol consumption can make people more sensitive to pain in two ways – through alcohol intake and alcohol withdrawal, says a study just published in the British Journal of Pharmacology.
The findings could help in developing drugs to battle alcohol-associated chronic pain and hypersensitivity in the 29.5 million people in the United States who have alcohol use disorder, the researchers said.
"There is an urgent need to better understand the two-way street between chronic pain and alcohol dependence," Marisa Roberto, senior author and a professor of neuroscience at Scripps Research, said in a news release. "Pain is both a widespread symptom in patients suffering from alcohol dependence, as well as a reason why people are driven to drink again."
The research team studied three groups of mice: some dependent on alcohol, some that were not dependent but had limited access to alcohol, and some that had no access to alcohol.
During withdrawal, dependent mice developed allodynia, in which a harmless stimulus feels painful. The dependent mice also showed decreased pain sensitivity when they got alcohol again. Mice with limited alcohol access also showed increased pain sensitivity during withdrawal, but unlike the dependent mice did not show decreased sensitivity when they were given alcohol again.
Researchers measured inflammatory proteins and found an increase in the dependent mice. Those proteins could be used in creating drugs, the researchers said.
“These two types of pain vary greatly, which is why it is important to be able to distinguish between them and develop different ways to treat each type,” said first author Vittoria Borgonetti, a postdoctoral associate at Scripps Research.
The news release said more than half the people with alcohol use disorder (AUD) have some sort of persistent pain, including nerve damage that causes chronic pain. AUD is also associated with changes in how the brain processes pain signals and how the immune system activates, which could lead to more drinking.