Bile acids that aid in fat digestion may reduce the rewarding properties of cocaine use, suggesting potential new strategies for treatment of drug abuse, a study has found.

The findings showed that bile diversion surgery -- an experimental treatment for weight loss by increasing the amount of bile acids that enter the general circulation -- lowered dopamine release in response to cocaine. Further, mice that received the surgery also had lower craving for cocaine. "These findings redefine the physiological significance of bile acid signalling and highlighting the importance of determining whether bile acid analogues represent a viable pharmacological treatment for cocaine abuse," said Aurelio Galli from the University of Alabama in the US.

For the study, published in the journal PLOS Biology, the team administered a drug called OCA -- semi-synthetic bile acid -- in mice that mimicked the effect of bile at its brain receptor named TGR5. The results provided evidence to show that elevated levels of bile after the surgery reduced the preference for cocaine. Knocking out TGR5 from the brain's nucleus accumbens -- a central reward region -- prevented bile acids from reducing cocaine's effects, confirming that signalling through this receptor was responsible for the cocaine-related results of bile acid elevation. The findings also contributed to a greater understanding of how gut-based signalling influenced higher order central functions such as reward.