Oxytocin reactivity to an emotional challenge paradigm and its relation to social-cognitive functions in healthy volunteers

The neuropeptide oxytocin (OT) is known to be an important modulator of social cognition. It has been shown that lower OT plasma concentrations are linked to impairments in social cognition. Studies have also shown that intranasal OT may enhance social-cognitive abilities in healthy subjects. We hypothesize that, besides baseline OT concentrations, the reactivity of the OT system may have an important role in social-cognitive functioning of individuals. In the present study, we explored if an emotional challenge paradigm is suitable to elicit OT release into plasma to make the reactivity of the OT system measurable. Therefore, 20 healthy male volunteers watched an emotional film clip, showing another person in pain during a severe dentist's treatment, while blood draws were conducted pre and post challenge. OT concentrations in plasma were measured by ELISA after solid phase extraction from plasma. OT plasma concentrations at baseline were significantly negatively correlated to an empathetic rating of our film clip and to measures of emotional empathy for positive and negative emotions, whereas the difference between post-challenge value and baseline was significantly positively correlated with the latter measures. Our data thus show that a short emotional video can be successfully employed as a challenge paradigm for eliciting an increase of peripheral OT in healthy male subjects. Calculating the relative OT change post- vs. pre-challenge may give a measure of OT reactivity. The combination of low peripheral OT at baseline with high OT reactivity may be a psychoendocrine trait that is linked to higher emotional functioning.