Drug that may curb drinking impulse identified

Melbourne: Scientists have identified a drug that may reduce cravings for alcohol by targeting the brain's immune system, which triggers the impulse to drink in the evening.

Alcohol is the world's most commonly consumed drug, and there is a greater need than ever to understand the biological mechanisms that drive our need to drink alcohol, said lead author, Jon Jacobsen, a PhD student in the University of Adelaide in Australia.

Researchers were able to switch off the impulse to drink alcohol by giving mice a drug that blocks a specific response from the immune system in the brain.

"Our body's circadian rhythms affect the 'reward' signals we receive in the brain from drug-related behaviour, and the peak time for this reward typically occurs during the evening, or dark phase.

"We wanted to test what the role of the brain's immune system might have on that reward, and whether or not we could switch it off," Jacobsen said.

Researchers focused their attention on the immune receptor Toll-like receptor 4 (TLR4). They administered the drug Naltrexone, which is known to block TLR4, to mice.

"Our studies showed a significant reduction in alcohol drinking behaviour by mice that had been given Naltrexone, specifically at night time when the reward for drug-related behaviour is usually at its greatest," researchers said.

"We concluded that blocking a specific part of the brain's immune system did in fact substantially decrease the motivation of mice to drink alcohol in the evening," they said.

The study was published in the journal Brain, Behavior, and Immunity.