Electro-acupuncture improves the social interaction behavior of rats

Oxytocin (OXT) and arginine-vasopressin (AVP) are two closely related neuropeptides and implicated in the regulation of mammalian social behaviors. A prior clinical study in our laboratory suggested that electro-acupuncture (EA) alleviated social impairment in autistic children accompanied by changes of peripheral levels of OXT and AVP. However, it remains unclear whether EA stimulation had an impact on central OXT and AVP levels. In the present study, rats were subjected to a single session of EA (sEA) or repeated sessions of EA (rEA). Following the stimulation, mRNA levels and peptide levels of OXT/AVP systems were determined. The results showed that sEA led to region-specific up-regulation of OXT and AVP mRNA levels in the hypothalamus where the peptides were produced, without affecting the content of OXT and AVP in the hypothalamus and peripheral blood. The rEA of 5 sessions in 9 days was given to the low socially interacting (LSI) rats. LSI rats that underwent rEA showed significant improvement of social behavior characterized by spending more time investigating the strange rats in the three-chamber sociability test. The improved sociability was accompanied by an up-regulation of mRNA and the peptide levels of OXT or AVP in SON of the hypothalamus as well as a significant increase of the serum level of AVP. It is concluded that activation of OXT/AVP systems may be associated with the pro-social effect caused by EA stimulation.