Psychology researchers at the University of Texas at El Paso are making progress toward understanding the biological underpinnings of depression, a leading cause of disability that affects approximately 280 million people worldwide.
In a study published this April in the Journal of affective disordersUTEP psychologist Sergio Iñiguez, Ph.D., and his coauthors argue that prairie voles, small rodents found throughout the central United States and Canada, can be effectively used as animal models to advance the study of clinical depression. .
“The findings of this research are important because we show, for the first time, that prairie voles show some of the core symptoms of depression after chronic exposure to stress, just like humans,” Iñiguez said. “This is exciting because we can now use this animal model to potentially uncover the biological factors underlying diseases such as depression and anxiety.”
The UTEP study focuses on the impact of bullying on the behavioral patterns of voles. The researchers looked at what happened when individual male voles were intimidated by more aggressive males over the course of ten days, inducing what Iñiguez calls “social defeat stress.”
Iñiguez explained that voles that were harassed exhibited changes in body weight, performed worse on spatial memory tests, and were less sociable with other voles compared to those that were not harassed. While voles generally show a preference for sugar water, bullied mice showed no preference when given a choice between regular water and sugar water, a pattern known as anhedonia, or loss of pleasure in usual activities, he said. Iñiguez.
Iñiguez and his fellow researchers concluded that “social defeat” activated the voles’ stress response and became a risk factor for symptoms that mirrored those of depression in humans.
Iñiguez, a professor in the UTEP Department of Psychology who studies behavioral neuroscience, said that while depression has certain defining characteristics, such as sadness, lack of pleasure in normal activities and altered sleeping and eating patterns, researchers don’t yet have a complete idea of what causes it.
“We have some information about the many factors that contribute to depression, but the ethical implications of conducting neurobiological research in humans make it difficult to identify the biology behind this debilitating condition,” Iñiguez said.
Rats and mice are often used in psychology studies, but prairie voles share several unique characteristics with humans that make them better candidates for research, such as having monogamous relationships, raising baby voles in pairs, and even assume parental roles for orphaned puppies.
Psychology doctoral student Minerva Rodríguez is the lead author of the study.
“These unique and special animals have opened doors to understanding aspects of depression that we simply couldn’t understand with mice and rats,” Rodríguez said. “Its distinct social behaviors provide new avenues for research, demonstrating the immense value of the prairie vole as a model for delving deeper into the neurobiology of depression induced by social stress.”
Future studies will examine how voles recover from depression-like experiences and how they respond to antidepressant medications such as Prozac or ketamine.
The project is funded by a grant from the National Institutes of Health.