Pharmacy researchers get grants to study hormone’s role in stress, mood disorders

By: Doug Bennett

Published: April 30th, 2015

Category: News, Pharmacodynamics News

Oxytocin is best known as the “love hormone” that is released during a hug or a kiss. Now, two University of Florida College of Pharmacy researchers have been awarded a pair of grants totaling $3.75 million to study its role in regulating the body’s response to stress and anxiety.

Knowing more about oxytocin’s role is a crucial step in understanding how it affects mood and anxiety disorders and preventing stress-related cardiovascular disease, according to the researchers. Anxiety disorders typically increase the risk of high blood pressure and cardiovascular disease.

Charles Jason Frazier, Ph.D., received a five-year, $1.875 million grant from the National Institute of Mental Health to study how oxytocin influences the brain structures that affect mood and social behavior. Eric Krause, Ph.D., secured a five-year, $1.875 million grant from the National Institutes of Health’s National Heart, Lung and Blood Institute. He will study how slightly elevated sodium levels cause neurochemical changes that reduce the impact of psychological stress. Frazier is an associate professor and Krause is an assistant professor in the College of Pharmacy’s department of pharmacodynamics.

Their work also may reveal more about why bingeing on certain foods can feel so good. Oxytocin, which facilitates breastfeeding and brings couples closer together, is also released in the brain after a salty snack.

“Some of the mechanisms we are investigating may help explain why eating a bag of potato chips when you’re down may help reduce stress and anxiety even as it raises your blood pressure,” Frazier said.

Krause’s work started with an observation during his postdoctoral studies: Animals that had some salt and got thirsty seemed less stressed and more social. That sparked his idea that sodium activated the neurons that produce oxytocin. Working together, Frazier and Krause found that modestly increasing an animal’s sodium level boosted its oxytocin level. Then Frazier made a key finding: Oxytocin inhibits the brain from releasing a neurotransmitter that causes anxiety and depression in animals. That helped validate Krause’s original idea that a little sodium is a potent stress-blocker.

Now, Krause will study how reducing the body’s response to psychological stress could prevent cardiovascular and mood disorders. To do that, he will look at how specific oxytocin receptors reduce anxious behavior and the cardiovascular system’s stress response by inhibiting a specific neurotransmitter.

Still, prodding the human body to reap the health benefits of producing more oxytocin isn’t as simple as boosting salt intake. Krause said that has its own hazards, including the risk of high blood pressure and cardiovascular disease.

Ultimately, he hopes to find new therapies that use the brain’s supply of oxytocin to reduce the effects of stress and anxiety.

Frazier’s work will focus on how the release of oxytocin in the hypothalamus possibly blunts the body’s stress response and inhibits a neurotransmitter that is suspected of causing many neuropsychiatric problems. The main goal is to understand how the release of oxytocin may be affecting different parts of the brain.

“With both of these studies, we’re trying to understand enough about how oxytocin signaling works that we can effectively identify new therapeutic targets and strategies that will alleviate anxiety and reduce the effects of the response to stress,” Frazier said.

In five years, Krause and Frazier expect to know a lot more about the locations in the brain where oxytocin is acting to relieve stress and anxiety. That should allow them to understand which treatment strategies would be most effective.

“The idea is to understand how elevated sodium levels dampen these particular aspects of stress, and how that can be exploited to develop new therapies one day,” Krause said.

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