Baixiangdan Capsule and Shuyu Capsule Regulate Anger-out and Anger-in: GB1 Mediated GABA Can Regulate 5-ht Level in the Dorsal Raphe Nucleus

Abstract Background: To explore the intervention mechanism of Baixiangdan Capsule(BXD) and Shuyu Capsule(SY) in the treatment of anger-out and anger-in. A kind of GABABR1(GB1) mediated GABA in the dorsal raphe nucleus(DRN) regulating serotonin(5-HT) levels in the Prefrontal Cortex(PFC), Hippocampus and Hypothalamus in Anger-out and Anger-in male rats. To further explore the difference of Baixiangdan Capsule(BXD) and Shuyu Capsule(SY) in the treatment of anger-out and anger-in.Methods: The anger rat model was established by social isolation combined with resident-intruder paradigm, and behavioral evaluation was used to screen and distinguish anger-out and anger-in model rats. BXD and SY were intervention drugs of anger–out and anger-in rats respectively. On this basis, ELISA was used to detect GABA content in DRN and 5-HT contents in PFC, hippocampus and hypothalamus after different time course (0,1,3,5,7 days) treated with BXD and SY. The co expression of 5-HT and GB1 in DRN was detected by immunofluorescence double labeling technique. Finally, brain stereotactic localization was performed after baclofen, the GB1 specific agonist, and CGP35348, the GB1 specific inhibitor, were injected into the DRN, the 5-HT contents in PFC, hippocampus and hypothalamus was detected by ELISA.Results: After drug treatment, ABT scores and OFT total distance in BXD group were significantly decreased to the level of control group (P<0.05). On the contrary, that in SY group were significantly increased to the level of control group (P<0.05). The sugar water preference coefficient of BXD group and SY group was significantly increased to the normal level (P<0.05). With the increase of the medication duration, 5-HT levels in PFC, hypothalamus and hippocampus increased, gradually corrected its abnormal decline, and returned to the normal level on the 7th day. Besides, GABA level in DRN decreased, gradually corrected its abnormal increase, and also returned to normal level on the 7th day. A large number of 5-HT positive cells (red) in DRN could be seen on immunofluorescence section, and GB1 positive cells (green) could also be seen. Besides, after the drug intervention, 5-HT level in DRN was elevated to normal level (P<0.05). GB1 level in DRN was decreased to normal level in BXD group and SY group (P<0.05). Compared with saline injection, 5-HT levels in PFC, hypothalamus and hippocampus in each group was significantly decreased after injection of baclofen into the DRN (P < 0.05). On the contrary, 5-HT levels in PFC, hypothalamus and hippocampus in each group was significantly increased after the injection of CGP35348 into the DRN.Conclusions: BXD and SY can effectively improve the abnormal behavior changes of anger-out and anger-in rats, and the optimal duration of action is 7 days. The improvement way is to correct the following abnormal changes: The significantly increased GABA in DRN combined with a significantly increased GB1 on 5-HT neurons in DRN, which further mediated the synaptic inhibition effect, thereby reducing 5-HT level of 5-HT neurons in DRN, resulting in a significant decrease of 5-HT levels in PFC, hypothalamus and hippocampus. Therefore, GB1 mediated GABA in DRN can regulate 5-HT levels in PFC, hypothalamus and hippocampus, which may be one of the ways that BXD and SY treat anger-out and anger-in.