I’m trying to determine what is different about people who develop drug addictions before they ever try a drug.
Professor Judith Grisel, psychology, is a behavioral neuroscientist with a particular interest in addiction. "I'm trying to determine what is different about people who develop drug addictions before they ever try a drug," she says.
Endorphins may be one influence, says Grisel, a C. Graydon and Mary E. Rogers Faculty Fellow for 2012-15. A natural form of morphine, endorphins are released by the pituitary gland in times of stress as a way of reducing anxiety. They also contribute to the pleasurable sensations we experience when drinking alcohol.
"Individuals with higher inherited endorphin levels appear to be less prone to alcoholism," she explains. "Those born with lower levels may find alcohol especially pleasurable since this drug increases endorphin levels. For them, alcohol provides a greater rush. But that can lead to addiction."
Grisel and her students study mice that have been genetically engineered with varying capacities to make and release endorphins. Their studies confirm that endorphins play an important role in feelings of pleasure from alcohol: Mice without endorphins don't find alcohol pleasurable, and they drink less.
In another study, Grisel gives mice the opportunity to run on an activity wheel and then allows them to drink alcohol for a short time each day. Under these conditions, the mice run enthusiastically and drink reasonably. But if denied the opportunity to run, the mice experience stress and drink more. This effect of stress from lack of exercise is also dependent upon endorphins.
Grisel's other research interests include studying sex differences in the role of stress and endorphins on drug reward (the tendency to binge-drink appears to be more common in females and castrated males), mapping genes that contribute to individual differences in drug reward and studying circadian influences on drug effects.
Grisel is proud that a number of her students will present their original research at the Society for Neuroscience's annual meeting in Washington, D.C., in November 2014. "One of my students will present a paper on beta endorphin and reward," she says. "She was a first-year student last year, and her name will appear first on the paper."
Posted Sept. 22, 2014
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