Using cutting-edge gene-editing technology, researchers have engineered prairie voles that lack oxytocin receptors. These notoriously monogamous mammals were thought to rely on oxytocin to form vital social bonds, but the results of these new experiments suggest that this so-called “love hormone” ‘ may not be as important as suspected.
Decades ago, ecologists discovered that male and female pairs of prairie voles, a species of rodent, always appear in traps together. Subsequent studies revealed that these species are among the few mammals that form pairs that are monogamous and can last a lifetime.
Laboratory studies of prairie voles in the 1980s and 1990s revealed an important role for the oxytocin hormone in shaping maternal and bonding behaviors in animals. When drugs were used to block oxytocin receptors, the animals’ ability to effectively form social bonds was reduced.
These prairie vole studies helped inform what we today understand to be the role of oxytocin in social relationships. There is even
For about 15 years, psychiatrist Devanand Manoli has been interested in the brain chemistry behind social bonding. So Manori collaborated with neurobiologist Nirao Shah to develop his own experiments. The pair were interested in finding out what would happen to prairie voles if they were genetically engineered to completely lack the oxytocin receptor from birth.
“Drugs can be dirty in the sense that they can bind to multiple receptors, and we don’t know which binding action is causing the effect,” Manoli explained. Removing one receptor and then eliminating its signaling pathway does not interfere with these actions. “
After much hard work based on recent CRISPR gene-editing innovations, researchers have successfully produced prairie voles that lack functional oxytocin receptors. and tested the social ability of animals to form social bonds.
It is no exaggeration to say that this result surprised the researchers. According to Manoli, the patterns of binding behavior in transgenic and normal voles were “indistinguishable.” Even without oxytocin receptors, animals bonded, huddled, and rejected new partners.
“Even after trying to test this in a variety of ways, we were all shocked that voles showed such strong social attachments to their sexual partners that they were as strong as their normal counterparts,” Manoli said. I was there,” he said.
The researchers then moved on to study the effects of oxytocin receptor signaling on parenting. Again, to the researchers’ surprise, the animals had no problem giving birth to offspring and then raising puppies.
The only significant effect the researchers noted was that oxytocin-deficient animals showed reduced lactation. , the genetically modified animals should not have been able to lactate at all. The result was very unexpected.
“This overturns conventional wisdom about lactation and oxytocin that has existed for much longer than pair bonding associations,” Shah explained. It’s textbook standard here, where we say, ‘Wait a minute, there’s more to it than that.'”
So what does this mean? Well, in a classic case of scientific uncertainty, it suggests that oxytocin isn’t the definitive hormone regulator for bonding and parenting that we had previously assumed. , says that the current model of oxytocin as a key “love hormone” is an oversimplification, and that this hormone likely plays a part in the larger story of mammalian bonding.
“These behaviors are so critical to survival that we cannot rely on this single point of potential failure,” Manoli added. There could be wiring, oxytocin receptor signaling could be part of that program, but it’s not the whole thing.”
And this is not just an academic finding that will impact science textbooks, this research will play a role in driving future clinical research aimed at treating human beings for social cognitive impairment. There have been previous studies investigating whether oxytocin could be used as a therapeutic tool for people with autism and schizophrenia, but these findings suggest that things may be a little more complicated than that. And thanks to this study, researchers now have a new experimental model using prairie voles to better investigate the clinical pathways that affect binding in mammals. doing.
“New genetic models such as Oxtr The prairie vole mutants we generated may better allow for rigorous dissection of the molecular and circuit mechanisms that mediate attachment behavior and its disruption in disease,” the researchers conclude in a new study. Relevant to neuropsychiatric disorders, molecular genetic approaches in prairie voles have made it possible to directly test the effects of such genetic perturbations in the context of complex social and attachment behaviors. ”
A new study was published in neuron.
Source: UCSF, Cellpress
