Dopamine type II receptors in amygdala along with oxytocin in hypothalamus regulate social behavior in male mandarin voles

The amygdala dopamine (DA) system and hypothalamic oxytocin (OT) play important roles in emotion regulation, and emotions are important in regulating social behavior. However, it is unclear whether DA in the amygdala is involved in the regulation of social behavior, and whether OT in the hypothalamus is also involved in this process. In this study, we examined the release of DA in the medial amygdala (MeA) during different social interactions and the effect of injecting the dopamine II receptor (D2R) agonist quinpirole and the D2R antagonist raclopride into the MeA on social behavior and OT in the paraventricular nucleus (PVN) and supraoptic nucleus (SON), as well as in the blood of male mandarin voles (Microtus mandarinus). The results showed that the DA in the MeA increased in the process of social behavior, and the DA in the face of strangers was higher than that in the face of familiars. In addition, the injection of D2R antagonists in the MeA reduced attacking and escaping behaviors but increased physical contact and investigating behaviors, increased the number of OT-IR neurons in the PVN and SON, and increased OT levels in the blood. While injection of D2R agonists in the MeA increased attacking and escaping behaviors but reduced physical contact and investigating behaviors, it also reduced OT-IR neurons in the SON. In conclusion, D2R in the medial amygdala and oxytocin in the hypothalamus regulate social behavior.