Oxytocin Ain't Behavin' How Scientists Thought It Would
Oxytocin amplifies love and bonding. But, it also intensifies fear and aversion.
Posted Sep 23, 2017
A new animal study from the University of California, Davis reports that after experiencing a negative social interaction (which was akin to being bullied) oxytocin receptors in an area of the brain associated with social anxiety became activated. This resulted in oxytocin-driven social isolation and avoidance behavior towards others. However, blocking this specific type of oxytocin receptors in a brain region—which is called the "anteromedial bed nucleus of the stria terminalis" or BNST—reduced stress-induced avoidance behaviors in female California mice who had been subjected to social defeat. These findings were published online Sept. 13 in the journal Biological Psychiatry.
Until recently, most experts believed that the neuropeptide oxytocin (OT) was worthy of colloquially being referred to as the “love hormone” or “cuddle molecule” because oxytocin appeared to consistently act as a type of prosocial glue that bonded people (and animals) together and fortified social connectedness. But, like most things in neuroscience, it turns out that oxytocin is much more complicated than originally hypothesized. The latest research suggests that oxytocin amplifies both positive and negative social experiences with equal intensity depending on which OT receptors in the brain are being modulated by this neuropeptide.
In 2013, researchers at Northwestern Medicine published a landmark paper, "Fear-Enhancing Effects of Septal Oxytocin Receptors,” in Nature Neuroscience. This was one of the first studies to identify the dark side of oxytocin. The researchers found that during and after experiencing social defeat or trauma, oxytocin targeted a specific area of the brain that reinforced fear-based memories.
The Northwestern scientists concluded that oxytocin—which had previously only been associated with positive valence linked to intimate pair bonding and falling in love—pumped up the volume of both emotional highs and emotional lows. While oxytocin amplified powerful feelings of social connectedness or being safe and sound, it also appeared to be the culprit behind intense gut-wrenching feelings of social isolation, loneliness, and heartbreak.
In a statement, Jelena Radulovic, professor of psychiatry, behavioral sciences, and pharmacology at Northwestern, who was senior author of this study said: "By understanding the oxytocin system's dual role in triggering or reducing anxiety, depending on the social context, we can optimize oxytocin treatments that improve well-being instead of triggering negative reactions."
These 2013 findings from Northwestern on the duality of oxytocin corroborate the latest OT receptor research from UC Davis published this month. Contrary to the popular misconception that oxytocin only fuels positive "cuddly" social interactions, Natalia Duque-Wilckens and Brian Trainor of the UC Davis Department of Psychology, College of Letters and Science also found that oxytocin intensifies the experience of both positive and negative social interactions.
In a statement, Trainor said: "Stressful social experiences appear to change which parts of the brain use oxytocin. Understanding how this works in a mouse gives us new ideas on how we could use drugs targeting oxytocin to reduce social anxiety." Duque-Wilckens and Trainor are optimistic that their research could lead to better treatments in the future stating, "Our results suggest that oxytocin receptor antagonists may have unappreciated therapeutic potential for stress-induced psychiatric disorders."
Duque-Wilckens, Natalia, Michael Q. Steinman, Marta Busnelli, Bice Chini, Sae Yokoyama, Mary Pham, Sarah A. Laredo et al. "Oxytocin receptors in the anteromedial bed nucleus of the stria terminalis promote stress-induced social avoidance in females." Biological Psychiatry (2017). DOI: 10.1016/j.biopsych.2017.08.024
Guzmán, Yomayra F., Natalie C. Tronson, Vladimir Jovasevic, Keisuke Sato, Anita L. Guedea, Hiroaki Mizukami, Katsuhiko Nishimori, and Jelena Radulovic. "Fear-enhancing effects of septal oxytocin receptors." Nature Neuroscience 16, no. 9 (2013): 1185-1187. DOI: 10.1038/nn.3465