Oxytocin has long been considered the ‘love hormone’, but this belief could start to shake. A study published this Friday in the journal ‘Neuron’ shows that this organic molecule is not necessary to establish lasting bonds with the couple and take care of the children.
The research was carried out with prairie voles or voles, rodents famous for their strong tendency to monogamy. After mating, these animals remain in pairs for the rest of their lives. They form very strong bonds and actively reject potential companions of the opposite sex. In addition, the male is involved to the same extent as the female in caring for the offspring. An example for our own species.
Previous studies using drugs to block oxytocin from binding to its receptor found that voles were unable to bind when hormone signaling was blocked. That is to say, his great qualities for love seemed to depend on this substance.
childbirth and rearing
Neuroscientists Devanand Manoli, from the University of California San Francisco (UCSF), and Nirao Shah, from Stanford, questioned this. They used the CRISPR gene-editing technique to generate voles that lack functional oxytocin receptors. They then tested whether these mutant mice could form lasting bonds with their mates. To their surprise, they did it just as easily as the normal ones.
A pair of voles. His ‘love’ is for life
The recipient was also expendable for childbirth and rearing. “Mutant voles can not only give birth, but also nurse,” says Shah. Both males and females engaged in the usual parental behaviors of snuggling, licking, and grooming, and were able to raise pups until weaning age. However, females had limited milk release. As a result, fewer pups survived to weaning age, and those that did were smaller.
The researchers believe that their results differ from those of other studies that used drugs to block oxytocin receptor signaling as a matter of precision. “Drugs can be dirty,” Manoli says, “in the sense that they can bind to multiple receptors, and you don’t know which binding action is causing the effect.” That’s not the case with genetics.
autism and schizophrenia
Another key difference is that while most pharmacological studies suppress oxytocin receptor signaling in adult animals, this study turned it off when voles were embryos. “We have made a mutation that starts before birth,” Shah reports. “It could be that there are compensatory or redundant pathways that are activated in these mutant animals and mask deficits in attachment, parental behaviors, and milk let-down,” he explains.
The illusion of an oxytocin spray to redirect a cheating wife or husband or even to solve more serious problems fades. “People expected oxytocin to be a powerful therapy to help people with social cognitive deficits like autism or schizophrenia,” Manoli says. “But this research shows that there probably isn’t a magic bullet for something as complex as social behavior,” she stresses.