We studied the effect of Saiko-ka-ryukotsu-borei-to (crude extract powder for research purposes) on central monoamine-related substances in mice. The formulation was given in a dose of 50mg/kg or 400mg/kg and was administered once or repeatedly (twice a day for seven days). The brain was removed and segmented in the conventional method. The monoamine-related substances were measured by a method using HPLC-ECD. The main results were as follows. The single or repeated administration of 50mg/kg increased DOPAC and HVA contents in the cerebral cortex. In the hypothalamus, the single 50mg/kg treatment decreased NE, and the repeated 50mg/kg treatment decreased NE but increased DOPA. In the corpus striatum, the single 50mg/kg administration increased DA, DOPAC, HVA, and 5-HIAA while the repeated administration increased NE and MHPG as well. In this region, the single 400mg/kg treatment increased NE and 5-HIAA, and the repeated treatment increased NE. In the hyppocampus, the repeated 50mg/kg treatment increased MHPG, and the repeated 400mg/kg treatment decreased HVA. These results indicate that the effect of this formulation on murine brain monoamines is greater at 50mg/kg than at 400mg/kg and that the effect varies among the regions of the brain.

In Chinese medicine, Saiko-ka-ryukotsu-borei -to (SRT; Chai-hu-jia-long-gu-mu-li-tang) and Saiko-keishi-kankyo-to (SKT; Chai-hu-gui-zhi-gan-jiang-tang) are frequently used for patients with nervous constitutions who exhibit psychoneurotic symptoms. Specifically, SRT is used for patients of the excessive constitution type (Shi Zheng), and SKT is used for patients of the deficient constitution type (Xu Zheng).
In this study, in order to clarify the action of SRT and SKT on the central nervous system, the effects of these formulas on the monoamines and their metabolism in discrete brain regions in mice were examined.
1) Single-dose administration of SRT and SKT increased the levels of neurotransmitters and stimulated the metabolism in the dopaminergic nervous system of the corpus striatum (including the serotonergic nervous system for SRT).
2) Repeated administration of SRT stimulated the metabolism in the dopaminergic nervous system of the hypothalamus and hippocampus, and inhibited metabolism in the adrenergic nervous system. On the other hand, SKT stimulated dopamine metabolism in the hippocampus and inhibited the metabolism of serotonin.
From these results, it became apparent that single-dose administration of SRT and SKT caused the hyperfunction of the dopaminergic nervous system, and that repeated administration of the agents caused the hyperfunction of the dopaminergic nervous system and the dysfunction of the serotonergic nervous system. This suggests that the actions of SRT and SKT on the central nervous systems may exert an influence on the regulation of psychoneuroic symptoms by stimulating the doperminergic nervous system and inhibiting the serotonergic nervous system.