Long Term Adult Relationships Cause Brain Changes that Reduce the Intensity of an Amphetamine High

If you’re a vole, pairing up with the love of your life protects you greatly against amphetamine addiction by reducing the drug's rewarding nature – an effect that may well occur slightly higher up the food chain - with humans - as well.

Researchers at Florida State University used voles, animals that form whole-life relationships with mates, to test the impact long term adult relationships have on the effects of amphetamine. They gave amphetamines to single (unpaired) voles and to adult paired voles and then looked at the brain cells of each to see if relationship status caused any difference in brain reaction to the drug.

They found that while amphetamine caused a similar dopamine release from the brain cells of all voles, amphetamine only caused increased dopamine binding for single voles. Paired voles actually saw an opposite effect from their ingestion of amphetamine - although they did experience an increased dopamine release, that release actually resulted in a lower than normal dopamine activation in the brain’s pleasure centers.

Dopamine release and the activation of dopamine receptors in areas like the nucleus accumbens in the brain cause the experience of intense pleasure. Dopamine is released in response to normal activities, such as eating or sex, and also after the ingestion of drugs like opiates, amphetamines, cocaine and others.

Study leader Zuoxin Wang commented on the significance of the research by saying, “Our results indicate that the pair bonding experience may alter the neurobiological response to drugs of abuse, which in turn may diminish the rewarding effects of the drug itself.”

In earlier research, Wang demonstrated that giving young unpaired voles unlimited access to amphetamine reduced their normal drive to form mating partnerships.

The full research results can be read in the June 1st edition of The Journal of Neuroscience.