Abstract
It has been known that oxytocin receptors are implicated in autism. Autistic subjects have been reported to have lower serum concentrations of oxytocin. Genetic linkage studies and single nucleotide polymorphism analyses for autistic disorder also show positive association of the oxytocin receptor with autism. Furthermore, mice lacking the oxytocin receptor gene show autistic phenotypes, such as socio-behavioral deficits. On the other hand, secretin, a gastrointestinal hormone, has been considered as a possible treatment for autism. However, the relationship between oxytocin and secretin remains to be determined. In the present study, we investigated whether secretin activates oxytocin neurons. We measured plasma oxytocin concentrations after an intracerebroventricular (icv) injection of secretin. The icv injection of secretin caused a dose-dependent increase in plasma oxytocin concentrations. The results indicated that secretin induces the activation of oxytocin neurons, consistent with a hypothesis that the effect of secretin on autism is mediated by oxytocin/oxytocin receptor system. [J Physiol Sci. 2006;56 Suppl:S216]
