Georgia State University scientists have created genetically modified hamsters for social neuroscience studies and find that the biology behind social behavior may be more complex than previously thought.
A team of researchers at Georgia State University led by Regents H. Elliot Albers and Distinguished Professor Kim Hohmann used CRISPR-Cas9 to eliminate actions of the neurochemical signaling pathway that plays a critical role in regulating social behaviors in mammals. Vasopressin and the receptor it acts on called Avpr1a regulate social phenomena ranging from pair bonding, cooperation, and sociability to dominance and aggression. The new study, published in Proceedings of the National Academy of Sciences (PNAS)found that elimination of Avpr1a receptors in hamsters, thus effectively eliminating the action of vasopressin on it, significantly altered the expression of social behavior in unexpected ways.
“We were really surprised by the results,” Albers said. “We expected that if we exclude vasopressin activity, we would reduce both aggressiveness and sociability. But the opposite happened.”
Instead, hamsters without the receptors showed significantly higher levels of social communication behavior than their counterparts with intact receptors. More interestingly, the typical gender differences observed in aggression were eliminated as both male and female hamsters showed high levels of aggression towards other individuals of the same sex.
“This points to an amazing result,” Albers said. “Although we know that vasopressin increases social behaviors by acting in a number of brain regions, it is possible that the global effects of Avpr1a receptors are inhibitory.
We do not understand this system as we thought. The nonsensical findings tell us that we need to start thinking about the actions of these receptors across entire circuits of the brain and not just in specific brain regions. “
The hamster used in the research was the Syrian hamster, which is becoming increasingly important for studies of social behavior, aggression, and communication. It is the species in which the effect of vasopressin on the community was first shown. Hamsters provide a powerful model for studies of social behavior because their social organization is much more similar to humans than that observed in mice, although mice are the most common laboratory animal. Hamsters are unique research animals in other ways, too, explained Hohmann, who is associate director of the Georgia State Institute of Neurosciences.
“Their stress response is more similar to that of humans than other rodents. They release the stress hormone cortisol, just as humans do. They also develop many of the cancers that humans do.” Their susceptibility to infection with the SARS-CoV-2 virus that causes COVID-19 makes them a strain Preferred rodents because they are just as susceptible to it as the rest of us.”
The researchers said working with CRISPR in hamsters was an important step forward. “Developing transgenic hamsters was not easy,” Albers said. “But it is important to understand the neural circuits involved in human social behavior and our model has translational relevance to human health. Understanding the role of vasopressin in behavior is essential to help identify new and more effective treatment strategies for a variety of neuropsychiatric disorders ranging from autism to depression.”
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