Brain region that influences binge drinking identified
New animal research from scientists at the Medical University of South Carolina has found binge drinking can be controlled by blocking a key brain region linked to emotion-related behavior. The mouse studies suggest blocking certain opioid receptors in the extended amygdala may curb excessive drinking.
“Binge drinking is a destructive behavior. And our goal was to curb that,” explains first author on the study, JR Haun. “Through our investigation, we found a brain region and a system that we can manipulate to decrease binge drinking.”
The research focused on investigating how the brain’s opioid receptor system influenced binge drinking behaviors. More specifically, the scientists were interested in kappa opioid receptors (KORs), a particular type of opioid receptor often linked to feelings of stress or discontent.
“The kappa opioid-receptor system is the antithesis to other opioid receptors,” says Haun. “It's often referred to as an anti-reward system.”
A volume of prior animal research has found stimulating KORs can result in a reduction of alcohol consumption. The hypothesis is that excessive KOR activity reduces the rewarding effect of drugs, leading to lowered consumption.
But, this new research suggests controlling some types of addictive behavior is not as simple as amplifying anti-reward brain pathways. In fact, the experiments in this study found blocking KOR activity in a certain part of the brain reduced binge drinking behaviors in a mouse model. Huan notes that, at this stage, it is unclear why this seemingly counterintuitive process works.
“It’s not entirely clear why,” says Haun. “But what we do know is that kappa opioid receptors play an important role in the negative emotional state that drives drinking when it becomes compulsive in alcohol use disorders.”
The study focused on an area of the brain occasionally referred to as the extended amygdala or, more specifically, the bed nucleus of the stria terminalis (BNST). This particular brain region is known to contain a high volume of KORs, and it has been linked to acute stress and anxiety responses.
The research discovered blocking KOR activity in the BNST resulted in the elimination of binge drinking behaviors in the mouse models. Interestingly, the animals did not stop drinking altogether, but instead simply moderated their drinking behavior.
“Blocking these kappa receptors in the extended amygdala didn't completely abolish drinking,” says Haun. “It brought it down to a more moderate level, the equivalent being a glass of wine at dinner opposed to a bottle.”
The ultimate hypothesis presented by the research is that binge drinking is somewhat stimulated by the release of stress-related peptides in the brain. This somewhat counterintuitive finding suggests that, while in some cases stimulating the body’s anti-reward KOR system can reduce alcohol-consumption and other addictive behaviors, in the context of excessive binge drinking, blocking KOR activity specifically in the extended amygdala actually results in moderated drinking behavior. This may be because underlying anxiety and feelings of stress are somewhat driving binge drinking activities, so if the neural pathway stimulating those feelings is blocked, then one may drink less.
It’s a compelling finding which sheds some light on the neurological processes at play in chronic heavy drinking. Howard Becker, corresponding author on the new study, suggests the discovery offers new research pathways to help treat those with excessive forms of alcohol use disorder.
“I think the ultimate goal is to better understand new potential treatment targets and how new therapeutics may have some value in helping to quell the desire and motivation to drink excessively in those who have developed an alcohol use disorder or are on the threshold of doing so,” says Becker.
The new research was published in the journal Neuropharmacology.