Researchers at Aalto University and University of Turku have discovered how altered opioid neurotransmission in the brain is connected to obesity.
Scientists found that obesity was associated with a significantly lowered number of opioid receptors in the brain. No changes, though, were observed in the dopamine neurotransmitter system, which regulates motivational aspects of eating.
It is possible that the lack of opioid receptors in the brain predisposes obese individuals to overeat to compensate for the decreased hedonic responses in this system, according to professor Lauri Nummenmaa and researcher Henry Karlsson.
The findings are important for understanding the causes of obesity. Researchers are gaining a better understanding of the mechanisms involved in overeating and new insight into behavioral and pharmacological treatment and prevention of obesity. However, it remains unclear whether the altered brain neurochemistry is a cause or consequence of obesity.
The researchers measured availability of mu-opioid and type 2 dopamine receptors in normal-weight and obese individuals’ brains using positron emission tomography at the Turku PET Centre.
The project was funded by the Academy of Finland, Sigrid Juselius Foundation and The Finnish Diabetes Research Foundation.
The findings were published March 3, 2015 in the Journal of Neuroscience.
Source: Aalto University and Turku PET Centre