Removing the Oxytocin Receptor Does Not Interfere with Monogamy or Offering Start
Turning a many years-outdated dogma on its head, new exploration from researchers at University of California, San Francisco and Stanford Medication reveals that the receptor for oxytocin, a hormone considered crucial to forming social bonds, may possibly not perform the significant function that scientists have assigned to it for the earlier 30 many years.
In the study, revealed on January 27, 2023, in the journal Neuron, the workforce discovered that prairie voles bred without receptors for oxytocin and showed the same monogamous mating, attachment, and parenting behaviors as normal voles. In addition, females without oxytocin receptors gave beginning and generated milk, although in lesser quantities, than regular female voles.
The results show that the biology underlying pair bonding and parenting isn’t purely dictated by the receptors for oxytocin, from time to time referred to as the “love hormone.”
“While oxytocin has been viewed as ‘Love Potion #9,’ it seems that potions 1 as a result of 8 may well be enough,” said psychiatrist Devanand Manoli, MD, PhD, a senior creator of the paper and member of the UCSF Weill Institute for Neurosciences. “This review tells us that oxytocin is probably just a person component of a a great deal additional advanced genetic program.”
CRISPR Voles Pack a Shock
Due to the fact prairie voles are one of the couple of mammalian
To the researchers’ surprise, the mutant voles formed pair bonds just as readily as normal voles.
“The patterns were indistinguishable,” said Manoli. “The major behavioral traits that were thought to be dependent on oxytocin – sexual partners huddling together and rejecting other potential partners as well as parenting by mothers and fathers – appear to be completely intact in the absence of its receptor.”
Labor and Lactation
Even more surprising for Manoli and Shah than the pair bonding was the fact that a significant percentage of the female voles were able to give birth and provide milk for their pups.
Oxytocin is likely to have a role in both birth and lactation, but one that is more nuanced than previously thought, Manoli said. Female voles without receptors proved perfectly capable of giving birth, on the same timeframe and in the same way as the regular animals, even though labor has been thought to rely on oxytocin.
The results help to clear up some of the mystery surrounding the hormone’s role in childbirth: Oxytocin is commonly used to induce labor but blocking its activity in mothers who experience premature labor isn’t better than other approaches for halting contractions.
When it came to producing milk and feeding pups, however, the researchers were taken aback. Oxytocin binding to its receptor has been considered essential for milk ejection and parental care for many decades, but half of the mutant females were able to nurse and wean their pups successfully, indicating that oxytocin signaling plays a role, but it is less vital than previously thought.
“This overturns conventional wisdom about lactation and oxytocin that’s existed for a much longer time than the pair bonding association,” said Shah. “It’s a standard in medical textbooks that the milk letdown reflex is mediated by the hormone, and here we are saying, ‘Wait a second, there’s more to it than that.’”
Hope for Social Connection
Manoli and Shah focused on understanding the neurobiology and molecular mechanisms of pair bonding because it is thought to hold the key to unlocking better treatments for psychiatric conditions, such as autism and schizophrenia, that interfere with a person’s ability to form or maintain social bonds.
Over the past decade, much hope was pinned on clinical trials using oxytocin to address those conditions. But those results were mixed, and none has illuminated a clear path to improvement.
The researchers said their study strongly suggests that the current model – a single pathway or molecule being responsible for social attachment –is oversimplified. This conclusion makes sense from an evolutionary perspective, they said, given the importance of attachment to the perpetuation of many social species.
“These behaviors are too important to survival to hinge on this single point of potential failure,” said Manoli. “There are likely other pathways or other genetic wiring to allow for that behavior. Oxytocin receptor signaling could be one part of that program, but it’s not the be-all end-all.”
The discovery points the researchers down new paths to improving the lives of people struggling to find social connection.
“If we can find the key pathway that mediates attachment and bonding behavior,” Shah said, “We’ll have an eminently druggable target for alleviating symptoms in autism, schizophrenia, many other psychiatric disorders.”
For more on this research, see Were We Wrong About the “Love Hormone” Oxytocin?
Reference: “Oxytocin receptor is not required for social attachment in prairie voles” by Kristen M. Berendzen, Ruchira Sharma, Maricruz Alvarado Mandujano, Yichao Wei, Forrest D. Rogers, Trenton C. Simmons, Adele M.H. Seelke, Jessica M. Bond, Rose Larios, Nastacia L. Goodwin, Michael Sherman, Srinivas Parthasarthy, Isidero Espineda, Joseph R. Knoedler, Annaliese Beery, Karen L. Bales, Nirao M. Shah and Devanand S. Manoli, 27 January 2023, Neuron.
Additional authors include: Ruchira Sharma, Rose Larios, Nastacia Goodwin, Michael Sherman and Isidero Espineda of UCSF, Maricruz Alvarado Mandujano, YiChao Wei, Srinivas Parthasarthy and Joseph Knoedler of Stanford, and Forrest Rogers, Trenton Simmons, Adele Seelke, Jessica Bond, and Karen Bales of UC Davis, and Annaliese Beery of UC Berkeley.
This work was supported by NIH grants R01MH123513, R01MH108319, DP1MH099900 and R25MH060482, NSF grant, 1556974, and philanthropy. For details, see the study.