Postnatal AVP treatments prevent social deficit in adolescence of valproic acid-induced rat autism model.

Studies have shown that arginine-vasopressin (AVP) is an important neuropeptide regulating social behaviors. The present work aimed to detect changes in the AVP numbers and level in a valproic acid (VPA)-induced rat model of autism and the underlying mechanism of its pathogenesis. Our results indicated that infants exposed to VPA showed obviously impaired communication and repetitive behaviors with reduced number of AVP-ir cells in paraventricular nucleus (PVN) and cerebrospinal fluid (CSF). The postnatal subcutaneous injection of AVP can alleviate social preference deficits and stereotyped behaviors, accompanied with the increase of the AVP concentrations in the CSF. We concluded that AVP system was involved in etiology of VPA-induced autism-like symptoms and postnatal AVP treatment rescued the behavioral deficits,which could be a promising treatment for autism.

Neonatal Oxytocin Treatment Ameliorates Autistic-Like Behaviors and Oxytocin Deficiency in Valproic Acid-Induced Rat Model of Autism.

Autism spectrum disorder (ASD) is characterized by impaired social communication and repetitive/stereotyped behaviors. The neuropeptide oxytocin (OXT) plays a critical role in regulating social behaviors in the central nervous system, as indicated in both human and animal studies. We hypothesized that central OXT deficit is one of causes of etiology of ASD, which may be responsible for the social impairments. To test our hypothesis, central OXT system was examined in valproic acid (VPA)-induced rat model of autism (VPA rat). Our results showed that adolescent VPA rats exhibited a lower level of OXT mRNA and fewer OXT-ir cells in the hypothalamus than control rats. Additionally, OXT concentration in cerebrospinal fluid (CSF) was reduced. The number of OXT-ir cells in the supraoptic nucleus (SON) of neonatal VPA rats was also lower. Autistic-like behaviors were observed in these animals as well. We found that an acute intranasal administration of exogenous OXT restored the social preference of adolescent VPA rats. Additionally, early postnatal OXT treatment had long-term effects ameliorating the social impairments and repetitive behaviors of VPA rats until adolescence. This was accompanied by an increase in OXT-ir cells. Taken together, we demonstrated there was central OXT deficiency in the VPA-induced rat model of autism, and showed evidence that early postnatal OXT treatment had a long-term therapeutic effect on the autistic-like behaviors in VPA rats.

Plasma Oxytocin and Arginine-Vasopressin Levels in Children with Autism Spectrum Disorder in China: Associations with Symptoms.

Autism spectrum disorder (ASD) is defined by impairments of social interaction and the presence of obsessive behaviors. The "twin" nonapeptides oxytocin (OXT) and arginine-vasopressin (AVP) are known to play regulatory roles in social behaviors. However, the plasma levels and behavioral relevance of OXT and AVP in children with ASD have seldom been investigated. It is also unknown whether their mothers have abnormal plasma peptide levels. Here, using well-established methods of neuropeptide measurement and a relatively large sample size, we determined the plasma levels of the two neuropeptides in 85 normal children, 84 children with ASD, and 31 mothers from each group of children. As expected, children with ASD had lower plasma OXT levels than gender-matched controls (P = 0.028). No such difference was found for plasma AVP concentrations. Correlation analysis showed that ASD children with higher plasma OXT concentrations tended to have less impairment of verbal communication (Rho = -0.22, P = 0.076), while those with higher plasma AVP levels tended to have lower levels of repetitive use of objects (Rho = -0.231, P = 0.079). Unlike the findings in children, maternal plasma OXT levels showed no group difference. However, plasma AVP levels in the mothers of ASD children tended to be lower than in the mothers of normal children (P = 0.072). In conclusion, our results suggest that the OXT system is dysregulated in children with ASD, and that OXT and AVP levels in plasma seem to be associated with specific autistic symptoms. The plasma levels of OXT or AVP in mothers and their ASD children did not seem to change in the same direction.

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.