Oxytocin, the so-called love hormone, increases our empathy and communication and helps regulate various other aspects of our social behavior. New research from UCLA has begun to advance oxytocin as a potential treatment for patients with Autism Spectrum Disorder (ASD). In a published study, mice modified to mimic autism were treated with oxytocin, which restored normal social behavior.
“The oxytocin system is a key mediator of social behavior in mammals, including humans, for maternal behavior, mother-infant bonding, and social memory,” Dr. Daniel Geschwind, a professor of psychiatry, neurology and human genetics, said in a press release. “So it seemed like a natural target for us to go after.”
While oxytocin is produced mainly in the hypothalamus, it eventually flows through the blood or moves to other parts of the brain and spinal cord, where it binds to receptors to influence physiology and behavior. Among the many roles it performs, oxytocin enables neurons to communicate with each other across various regions of the brain. In particular, oxytocin neurons in the hypothalamus interact with the amygdala, hippocampus, and frontal cortex, where they impact the processes of memory and social behavior. Oxytocin, then, is central to our experience of life and other people.
For the current study, Geschwind and his colleagues began by looking back at past work. In 2011, the research team had developed a mouse model for ASD. Through genetic modification, they eliminated from the mice one gene, CNTNAP2 (contactin-associated protein-like 2), which is believed to play an important role in the brain circuits responsible for language and speech. The genetically modified mice, just like autistic humans, showed little interest in interacting or socializing with other mice. Having created this model, Geschwind and his team could experiment to gain a better understanding of the condition.
Revisiting this mouse model, the researchers began with an examination of the brains of these genetically modified mice and discovered a decrease in the number of oxytocin neurons in the hypothalamus along with an overall decrease in oxytocin levels throughout the brain. Next, the researchers administered oxytocin to these genetically modified mice to see how it might affect them. As expected, sociability, defined as time spent interacting with other mice, increased. Next, the researchers gave the mice melanocortin, which activated cells, causing a natural release of oxytocin in brain cells and so improved the social behavior of the mice.
Unpredictably, the researchers found that giving the mice oxytocin earlier as opposed to later in their development led to longer positive effects. Geschwind’s next step will be to learn the limits and boundaries of treatment. If he can refine his understanding of oxytocin's therapeutic effect, he hopes he might someday help humans with this therapy.
Source: Penagarikano O, Lazaro MT, Lu X-U, et al. Exogenous and evoked oxytocin restores social behavior in the Cntnap2 mouse model of autism. Science Translational Medicine. 2015.