A recent peer-reviewed journal study neuron showed that prairie rats born without the ability to respond to oxytocin still formed strong bonds with their mates and pups.
“Oxytocin may be an important player, but it’s not the only game in town,” said study author Nirao Shah quirks and quarks presenter Bob McDonald.
Much of the research into oxytocin’s role in pair bonding has involved prairie voles. They are among the few mammals that, like humans, form long-term exclusive relationships, raise their young together, and even mourn the loss of their partners. And oxytocin has been found to be the key ingredient for many of these behaviors in both rats and humans.
The researchers previously studied what happened if the oxytocin signal was disrupted in rat brains by using drugs to block the oxytocin receptor – a sort of molecular gate that lets the hormone in. The results were devastating: the rodents did not mate and those that did have litters left their young to starve.
A team of researchers at Stanford University decided to see what would happen if, instead of blocking the “door” for oxytocin, rats were born with brains that didn’t have that door in the first place.
The researchers used the CRISPR gene editing technique to remove the oxytocin receptor in rat embryos.
“The advantage of genetics, especially the CRISPR technology being used, is that it’s a kind of molecular scissors that only makes the changes in the oxytocin receptor pathway and nowhere else,” said Shah, professor of psychiatry, neurobiology and midwifery and gynecology. at Stanford University.
They then observed how the rats behaved with each other and with rodents that had an intact oxytocin receptor system. In particular, the scientists looked for pair bonding behaviors. These included huddles, where voles snuggle up to their mates for a long time, along with voles showing an obvious preference for hanging out with their chosen mates over other rodents.
The results shocked scientists.
“To our surprise, these animals that lacked the oxytocin receptor showed, for all intents and purposes, perfectly normal social attachment behaviors,” Shah said.
“No matter how many different ways we tried to test this, the rats demonstrated a very robust social attachment to their sexual partner, just as strong as their normal counterparts,” said study co-author, psychiatry researcher Devanand Manoli of the University of California, California. San Francisco. said in a press release.
Furthermore, rats lacking the oxytocin receptor have proven to be good parents, raising their small litters of young until weaning.
Love finds a way
These study results offer a glimpse into how oxytocin shapes the brain mechanisms responsible for social behavior, says Larry Young, a professor in the department of psychiatry at Emory University in Atlanta, who was not part of the research team for this study. Young has extensively studied the role of oxytocin and vasopressin in social bonding and empathy in prairie rats as part of his work at the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory University.
“This suggests that oxytocin is shaping brain circuits in some way,” he said. quirks and quarks in a telephone interview. “So if you’re born with it, you’re wired in such a way that your circuitry depends on it. But if the animals don’t have any receptors from birth, there’s some kind of adaptation in the circuitry or in other genes to allow them to be able to perceive social interactions in the absence of oxytocin.”
As an analogy, explained Young, if you have a conductor-led orchestra and suddenly the conductor is absent, the music can get out of sync. But if you have a street band that is training with no conductor, they can still play great music.
“I think the oxytocin is being the driver,” Young said.
Shah said other brain mechanisms may be at play when it comes to social bonding in prairie rats born without the oxytocin receptors.
“There may be other hormonal signaling pathways that work really well even in the absence of oxytocin. So if you knock out one, the other pathway is still there and can give you normal social attachment behavior,” he said.
Another possibility is that the rats evolved another way of processing oxytocin to compensate for the missing receptors – because, unlike the rodents in previous studies who had their oxytocin receptors blocked with drugs, the rats in this study lacked them from birth.
These findings help deepen our understanding of the role hormones like oxytocin play in vole and human behavior. previous searches explored using oxytocin in the treatment of social cognitive impairments such as autism spectrum disorders or schizophrenia. But Shah says the current study requires a more nuanced approach.
“While oxytocin can be important, just putting oxytocin back or giving you more oxytocin doesn’t give you the ability to magically bond,” Shah said.
“So our understanding needs to be more nuanced, are there other actors or other signaling routes for oxytocin that we need to discover.”
Written and produced by Olsy Sorokina