Sansoninto (SAT) is prescribed for annoyance and insomnia. We previously demonstrated SAT attenuates aggressive behavior in social isolation-reared (SI) mice. However the mechanism by which SAT attenuates aggression is still unknown. Arginine vasopressin (AVP) plays a critical role in the regulation of aggression in mammals. AVP is regulated by 5-HTergic and DAergic systems. In this study, the effect of SAT on expression of 5-HTergic and DAergic system-related genes and AVP was examined using SI mice.
SAT was treated for 2 weeks. Group-reared (GR) mice were used as control. AVP level in bed nucleus of the stria terminalis was measured by EIA. Expression of 5-HTergic and DAergic system-related genes were analyzed by qPCR.
SI mice showed higher AVP level than GR mice. SAT-treated SI mice showed lower AVP level as much as GR mice. Catechol-O-methyltransferase (COMT) and 5-HT3a receptor mRNA level was higher in hypothalamus and amygdala of SI mice compared with GR mice. SAT-treated SI mice showed lower level of COMT and 5-HT3a receptor mRNA in hypothalamus, not in amygdala, than SI mice.
These results suggest that SAT reduces the increased AVP level via regulation of hypothalamic 5-HTergic and DAergic systems.