ICYMI

ICYMI: Love Conquers Experiment: Prairie Voles Born Without Oxytocin Receptors Still Pair Bond, Upending Decades Of Dogma

  • Published9 Feb 2023
  • Author Christine Won
  • Source BrainFacts/SfN
Prairie Voles
Shutterstock.com via Maximillian cabinet

For over three decades, oxytocin has been touted as “the love hormone,” credited with driving social behaviors like snuggling, grooming, and pair bonding in prairie voles.

However, a new genetic study suggests the rodents — long known for their tendency to cuddle and mate for life — will permanently bond with their partner, oxytocin or not. The potentially field-altering findings were published January 27 in Neuron.

Prairie voles, the furry, cuddly model of monogamy, have long been the animal model of choice for researchers investigating social behavior. In study after study, previous research corroborated this strong link between the rodents’ loving behavior and oxytocin: Triggering oxytocin sparked lovey-dovey affection, while blocking it elicited rejection behaviors.

So when researchers used CRISPR gene editing to eliminate oxytocin receptors in fertilized eggs of pregnant prairie voles, they expected to see corresponding loveless behavior like rebuffing mates or neglecting offspring. However, despite the lack of oxytocin receptors, these voles continued loving up their mates and pups, upending decades of research dogma rooted in the once-sure connection between pair bonding and oxytocin.

The results so baffled scientists they repeated the tests three times to net the same results.

Big Picture: So the connection between oxytocin and pair bonding may not be as cut-and-dry as previously believed. There may be a couple explanations for this.

It is possible that oxytocin has more than one hormone receptor it can bind to, which is something other studies have previously suggested.

Or — more radically — when oxytocin, lacking its normal receptors, became more or less defunct, that in turn forced other parts of the brain to adapt and rewire to make up for its absence. This would make sense from an evolutionary standpoint as the prairie vole survival depends on pair bonding. 

In this latest study, the oxytocin receptor was removed before birth by gene editing, whereas previous experiments had blocked the receptors in adult animals. Like with love, it could be a matter of timing.

Read MoreScientists Tried to Break Cuddling. Instead, They Broke 30 Years of Research. The Atlantic

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BrainFacts/SfN

Berendzen, K. M., Sharma, R., Mandujano, M. A., Wei, Y., Rogers, F. D., Simmons, T. C., Seelke, A. M. H., Bond, J. M., Larios, R., Goodwin, N. L., Sherman, M., Parthasarthy, S., Espineda, I., Knoedler, J. R., Beery, A., Bales, K. L., Shah, N. M., & Manoli, D. S. (2022). Oxytocin receptor is not required for social attachment in prairie voles. Neuron, S0896-6273(22)01084-4. Advance online publication. https://doi.org/10.1016/j.neuron.2022.12.011