Gene Dog Blog

Obesity is a hot topic among many modern first world issues, in part due to the complexity of the issue. It can result from a variety of possible genetic and environmental factors, and the relationship between these two factors can vary greatly for any given case of obesity.

I read a recent article which examined the neuromodulators and neurotransmitter systems involved with reinforcing properties of food. Essentially, when you eat, your brain releases a whole slew of chemicals (dopamine, opioids, serotonin). The article found a good amount of evidence to suggest that dopamine (DA) may be the neurotransmitter that most strongly links the genetic and environmental factors which contribute to obesity. Most of this evidence pointed to previous studies involving rats that demonstrated DA D2 receptor antagonists can enhance meal size and duration of feeding.

Trying to find the role of DA in addiction was a bit more difficult of an undertaking. Animal studies have shown that cocaine, the most reinforcing of abused drugs, blocks the dopamine transporters, which leads to compulsive drug administration. DA D2 receptor levels have been shown to mediate reinforcing responses to drugs of abuse. Those with lower DA D2 receptor levels have demonstrated more feelings of pleasantness and euphoria when dosed with a stimulant drug, methylphenidate. However, this only links people with lower DA D2 receptor levels to having a higher inclination to liking drugs rather than having a higher likelihood to become addicted. That being said, there have also been studies demonstrating higher levels of addiction in individuals with reduced DA D2 receptors, reflecting a “Reward Deficiency Syndrome” that is less sensitive to reward stimuli. Essentially, those with lower dopamine receptor levels are less fulfilled by activities that induce the release of dopamine.

This idea about “Reward Deficiency Syndrome” seems to link almost seamlessly to overeating as having a lower sensitivity to reward stimuli would make people more vulnerable to food intake as a way to compensate for this perceived deficit. This raises interesting possibilities in the treatment of obesity as one possible treatment might involve improving DA function. This type of creativity used to find parallels between seemingly disparate activities (obesity and drug abuse) is not only a fascinating to think about, but also bears amazing practical implications.

By-line:

Mariana Ashley is a freelance writer who particularly enjoys writing about online colleges. She loves receiving reader feedback, which can be directed to mariana.ashley031 @gmail.com.