Sluggishness: Maybe It’s the Missing Dopamine

Drug addiction changes human brains. One of those changes is a depletion of dopamine receptors. In obesity, dopamine and its receptors may have a role, but many questions remain. And now, new animal research raises yet another question. Could it be that changes in dopamine receptors make physical activity more difficult in obesity?

Danielle Friend and colleagues studied the effects of obesity on D2 dopamine receptors (D2Rs) in mice. Then, to address questions about causality, they looked at the effects of missing D2Rs on the risk of weight gain. Perhaps inactivity is as much a result of obesity as it is a cause, they say:

We conclude that deficits in striatal D2R signaling contribute to physical inactivity in obesity, but inactivity is more a consequence than a cause of obesity.

Of course, it’s a big leap from mice to humans. Only with much more research will we know the true answers to the questions raised here. And we humans are fond of saying that biology is not destiny. But ignoring biology is a foolish mistake.

“We must believe in free will. We have no choice.” – Isaac Bashevis Singer

Click here for the study and here for

Reduced Dopamine Receptors. Image from Fowler et al, 2007, “Imaging the Addicted Human Brain.”

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January 3, 2017