The neuropeptide oxytocin, known for promoting social interactions, has attracted interest as a possible treatment for autism spectrum disorder. A challenge is getting the molecule past the blood-brain barrier. Many clinical studies have used delivery via nasal spray, but even then, oxytocin doesn’t last long in the body and shows inconsistent effects.
Emory neuroscientist Andrew Escayg has been collaborating with Mercer/LSU pharmacologist Kevin Murnane on a nanoparticle delivery approach that could get around these obstacles. One of Escayg’s primary interests is epilepsy — specifically Dravet syndrome, a severe genetic form of epilepsy — and oxytocin has previously displayed anti-seizure properties in animal models.
Escayg and Murnane’s recent paper in Neurobiology of Disease shows that when oxytocin is packaged into nanoparticles, it can increase resistance to induced seizures and promote social behavior in a mouse model of Dravet syndrome.
This suggests properly delivered oxytocin could have benefits on both seizures and behavior. In addition to seizures, children and adults with Dravet syndrome often have autism – see this Spectrum News article on the connections.
Escayg reports he is planning a collaboration with oxytocin expert Larry Young at Yerkes, who Tweeted “This is a promising new area of oxytocin research” when the paper was published. Senior postdoc Jennifer Wong has already been working on extending the findings to other mouse models of epilepsy and adding data on spontaneous seizure frequency.
Different levels of a receptor for a hormone involved in social bonding may explain individual variation in offering comfort during stressful situations. Like humans, animals console each other in times of distress: monkeys hug and kiss, and prairie voles groom each other.
James Burkett, PhD
Emory postdoc James Burkett described his research on voles at a press conference on “The Neuroscience of Emotion and Social Behavior” at the Society for Neuroscience meeting in San Diego on Sunday. Here are Video (Burkett’s part is roughly from 4:50 to 9:00) and the scientific abstract.
Burkett’s presentation, on oxytocin-dependent comforting behavior in prairie voles, outlined an extension of his graduate work with Larry Young at Yerkes National Primate Research Center, which was published in Science in January 2016 and impressed oxytocin skeptic Ed Yong. Burkett, now in Gary Miller’s laboratory at Rollins School of Public Health, also masterminded a Reddit “Ask me anything” in February.
The rest of the Society for Neuroscience press release:
Previous research indicates oxytocin—a hormone that promotes social and maternal bonding—acts in the anterior cingulate cortex (ACC) of the prairie vole brain to encourage consoling behavior. In humans, the ACC activates when people see others in pain. Some degree of personal distress motivates comforting behaviors, but too much actually makes animals (including humans, chimpanzees, and rats) less likely to offer comfort.
ScientistsÂ at New York University found that oxytocin helps to focus the brains of new mother mice on their pups’ calls — specifically acting on a region of the brain responsible for processing sound. The paper was published in NatureÂ — with a companionÂ News + Views from Liu.
NatGeoÂ blogger Ed Yong has been a critic of the “love hormone” hype surrounding oxytocin, and he and Young seem to have had a meeting of the minds on thisÂ Nature paper.
â€œThis kind of study, which gets into details and doesnâ€™t attribute fluffy psychological traits to this molecule, is exactly what we need to move the field forward,” LY tells EY.
Please head over to our sister blog eScienceCommons to learn about how two types of white-throated sparrow have differences in behavior, which are driven by a chromosomal alteration. Scientists at Emory showed that changes in the estrogen receptor gene are responsible for the behavior differences.
Oxytocin, a peptide hormone first studied for its roles in childbirth and lactation, has been a hot topic recently, partly because of excitement around the idea of using it to treat autism spectrum disorders. (There has even been a bit of a backlash.)Â Larry Young is quoted extensively in Greg Miller’sbalanced take on oxytocin in Science:
“In my view, the best benefit from stimulating the oxytocin system is going to be to combine it with a controlled behavioral therapy,” Emory’s Young says. He believes that oxytocin’s main effect is to make people more sensitive to social cues. In a therapist’s office, children could be assured of receiving positive, reinforcing social cues while under the hormone’s sway. Not so if they cheap oakley sunglasses simply take the hormone and went about their day. “Say you give it to a kid and then he goes to school and gets bullied. That’s not going to have a positive impact, and it may even make things worse,” Young says.
A better handle on the basic biology of intranasal oxytocin, such as how it enters the brain and which receptors it hits, might enable researchers to develop more effective drugs, Young adds. “If we want to move beyond this initial investigatory era and get more sophisticated and potent effects, we need to understand the mechanisms.”
Young, who is world-renowned for his work on the role of neuropeptides in regulating social behavior, uses voles to investigate the neurobiological and genetic mechanisms underlying social behavior. Using the monogamous prairie vole (vs. the promiscuous meadow vole) as a model organism, Young and his research team identified the oxytocin and vasopressin receptors as key mediators of social bonding and attachment. In addition, they are examining the consequences of social bond disruption as a model of social loss-induced depression.
This work has important implications for developing novel treatment strategies for psychiatric disorders associated with social cognitive deficits, including autism spectrum disorders and schizophrenia.