Ninjinyoeito exerts an antidepressant‐like effect by enhancing the central noradrenergic system

Aim Ninjinyoeito (NYT) is a Kampo medicine prescribed for patients with decreased mental and physical energy. Clinical studies demonstrate that NYT ameliorates depressive symptoms in various diseases. However, the underlying therapeutic mechanisms of action remain unclear. The monoaminergic system has been implicated neuropathology depression. Using immobility tail suspension test to evaluate depression-like behavior, we aimed examine effects involvement α1-adrenoceptor serotonin (5-HT)1A receptor its mechanism action. Methods Immobility was used as an index behavior. (1,000 or 2,000 mg/kg/day, once day seven days) orally administered mice. Prazosin WAY-100635 were 30 min 1 h before test, respectively. Norepinephrine (NE) 5-HT levels frontal cortex amygdala analyzed using high-performance liquid chromatography (HPLC) electrochemical detector. Results (2000 mg/kg/day) shortened time. blocked NYT-mediated reduction increased NE levels, but not amygdala. Conclusion reduced time likely by increasing levels. may activate α1-adrenoceptor, thereby ameliorating therefore improve enhancing noradrenergic system.