JAPAN: The “love hormone,” oxytocin, has long been believed to be essential for behaviours like mating with a mate and raising offspring, but a recent study on prairie voles is casting doubt on this theory.
The researchers discovered that oxytocin receptor-deficient voles could still form solid bonds, give birth to young, and nurse—behaviours previously thought to be hormone-dependent.
One of the few mammal species that establish lifelong pairs, prairie voles are frequently employed to study human social behaviours, including pair formation.
When voles were given chemicals that stopped them from processing oxytocin, they stopped getting together, and the mothers stopped feeding their young.
Devanand Manoli, a psychiatrist, and Nirao Shah, a neurobiologist, created genetically altered prairie voles without functional oxytocin receptors, and they then watched how the mutant male and female voles behaved.
To their surprise, the mutant female voles could still give birth and nurse young, unlike those in the drug-driven tests, and the mutant voles seemed to have no trouble mating with non-genetically altered partners.
The University of California, San Francisco assistant professor Manoli stated, “We were startled.”
The findings imply that oxytocin is not the primary or exclusive motivator of behaviours like pairing or nursing, he said.
According to him, behaviours that are so essential to the species’ survival don’t have a “single point of failure,” as revealed by genetics.
But that didn’t mean no distinctions existed.
Some male mutant voles paired with regular female companions lacked the typical hostility toward trespassing females.
According to the study, while mutant females did conceive and nurse litters, some of them had fewer pups per litter, and fewer of their offspring survived to wean than their counterparts.
Mutant mothers also typically give birth to lighter puppies, which may indicate that they are less successful nurses.
Only “wild-type” couples were used in the study, and the researchers noted that pairings with two mutant partners would have different outcomes.
Nevertheless, the results as a whole paint a different picture of oxytocin’s function in a number of crucial behaviours.
According to Shah, a scientist from Stanford University, this might be due to animals that were grown without receptors developing “alternative compensating pathways” that enabled them to pair up and suckle.
However, the researchers hypothesise that it probably means oxytocin is simply one of several genetic variables that regulate social behaviour.
“Our experiments, in my opinion, show that numerous pathways regulate these really complicated behaviours,” said Manoli.
Oxytocin has sometimes been suggested as a treatment for attachment problems and other neuropsychiatric disorders, even though there isn’t much solid evidence to back it up.
The current research aims to determine which additional hormones and receptors may play a role in behaviours like pairing and nursing.
Manoli stated that “these other pathways might function as novel therapeutic targets.”
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