Novel dopamine receptor agonist in the brain may halt binge eating behaviour

A team of researchers from Boston University School of Medicine (BUSM) and the Roche Innovation Centre Basel lab, in Switzerland, has identified a compound capable of regulating the expression of a brain receptor involved in addictive behaviours.
The rise in food addiction disorders, such as uncontrollable cravings for highly processed foods, is contributing to increasing rates of obesity and type 2 diabetes.
Researchers have recently discovered that regular high consumption of sugar turns on the same intracellular brain receptor that amphetamine-like drugs activate.
This receptor is the trace amine-associated receptor (TAAR)1, and is known to modulate dopaminergic activity – in parts of the body that produce or are affected by dopamine – which is associated with drug reward.
Previous research has shown that the overexpression of TAAR1 in the cells in response to stimuli, such as amphetamine use or the consumption of highly palatable food, leads to cellular adaptations in dopaminergic neurons.
These adaptations cause cellular tolerance, which in turn drives the compulsive seeking and taking of even greater quantity of a drug or, in some cases, junk food.
In this study, researchers found that a certain TAAR1 agonist – a chemical that binds to the TAAR1 receptor and causes its downregulation – called RO5256390, may help reduce the behavioural effects of addiction triggered by binge eating.
Professor Pietro Cottone, the study co-author from BUSM, and his colleagues knew that TAAR1 agonists had shown many beneficial effects on substance abuse in rodents, and were confident that this might be the case for compulsive eating too.
The findings, published in the journal Neuropsychopharmacology, show that the TAAR1 agonist RO5256390 may be able to decrease the spike frequency of dopaminergic neurons fuelling the addiction due to prominent expression of TAAR1 in mice.
Specifically, the rats tested that had an addiction to sugary, chocolate-flavoured treats reduced their food consumption and stopped overreacting to cues associated with junk food after receiving RO5256390.
It is thought that attenuating TAAR1 expression via its agonist, RO5256390, could bring the dopaminergic activity down, thus breaking the cycle of addiction.
Overall, the results reveal that controlling TAAR1 expressio, which in part regulates dopamine release in addictive behaviours, can curb binge eating.