Oxytocin and social contact reduce anxiety: Hormone may be less effective at relieving stress for isolated animals

The study was presented at Neuroscience 2010, the annual meeting of the Society for Neuroscience, held in San Diego.

"Work in the last two decades has propelled oxytocin toward the top of a list of potentially effective stress- and anxiety-reducing agents, largely due to its positive associations with mental health," said Jason Yee, PhD, a postdoctoral fellow in the laboratory of Sue Carter, PhD, at the University of Illinois at Chicago.

To explore oxytocin's effectiveness in relieving stress, Yee and his colleagues treated voles with oxytocin and then placed them in a wet cage, a stressor that mimics a flooded burrow the voles might experience in the wild. Then the researchers allowed the voles to recover in a dry cage, either by themselves or with another vole.

Most of the voles tried to escape the dry cage -- an anxious behavior. However, the voles that received oxytocin and recovered with a companion showed less escape behaviors. These voles had high levels of oxytocin in their blood. In contrast, oxytocin was less effective at reducing anxious behaviors in voles that recovered by themselves. These voles had lower levels of oxytocin in their blood.

"When animals receive oxytocin and are given an opportunity to recuperate in the presence of a familiar partner, their bodies may release extra oxytocin, which in turn appears to facilitate a less anxious pattern of behavior," Yee said. The findings suggest that social contact is an important factor in oxytocin's ability to reduce anxiety.

Research was supported by the National Institute of Mental Health and the National Institute on Aging.