Research Paper Volume 15, Issue 6 pp 2046—2065

Baixiangdan capsule and Shuyu capsule regulate anger-out and anger-in, respectively: GB1–mediated GABA can regulate 5-HT levels in multiple brain regions

Xiaoju Liu1, *, , Haijuan Wang2, *, , Xiaoyu Wang3, , Yinxia Ning3, , Wei Liu4,5, , Jie Gao3, ,

  • 1 Shandong University of Traditional Chinese Medicine, First Clinical Medical College, Jinan, China
  • 2 Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
  • 3 Shandong University of Traditional Chinese Medicine, College of Traditional Chinese Medicine, Jinan, China
  • 4 Department of Encephalopathy, Shandong University of Traditional Chinese Medicine Second Affiliated Hospital, Jinan, China
  • 5 Shandong University of Traditional Chinese Medicine, Office of Academic Research, Jinan, China
* Equal contribution and share first authorship

Received: October 19, 2022       Accepted: February 13, 2023       Published: March 21, 2023      

https://doi.org/10.18632/aging.204589
How to Cite

Copyright: © 2023 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

The identity of the mechanism by which the Baixiangdan capsule (BXD) and the Shuyu capsule (SY) control anger-out (AO) and anger-in (AI) in rodents is unclear. The current study clarified the intervention role of BXD and SY on AO and AI male rats. We further explored the differences between BXD and SY in the treatment of AO and AI rats. Social isolation combined with the resident-intruder paradigm was used to establish the anger-out and AI rats models. On this basis, GABA content in the dorsal raphe nucleus (DRN) and serotonin (5-HT) contents in these brain regions were detected using ELISA after various time courses (0, 1, 3, 5, and 7 days) treated with BXD and SY. Co-expression of 5-HT and GB1 in the DRN was detected. GB1-specific agonist baclofen and GB1-specific inhibitor CGP35348 were injected into the DRN. Changes in 5-HT levels in these brain regions were then detected. After treatment, rats in the BXD group exhibited lower aggressive behavior scores, longer latencies of aggression, lower total distances in the open field test, and a higher sucrose preference coefficient. Meanwhile, rats in the SY group exhibited higher aggressive behavior scores, shorter latencies of aggression, higher total distances in the open field test, and higher sucrose preference coefficients. With increasing medication duration, 5-HT levels in these brain regions were increased gradually, whereas GABA levels in the DRN were decreased gradually, and all recovered to normal levels by the 7th day. A large number of 5-HT-positive cells could be found in the immunofluorescence section in the DRN containing GABABR1 (GB1)-positive cells, indicating that 5-HT neurons in the DRN co-expressed with GB1. Furthermore, after the drug intervention, the 5-HT level in the DRN was elevated to a normal level, and the GB1 level in the DRN was decreased to a normal level. After the microinjection of baclofen into the DRN, the 5-HT contents in these brain regions were decreased. By contrast, the 5-HT contents were increased after injection with CGP35348. BXD and SY could effectively improve the abnormal behavior changes of AO and AI rats, and the optimal duration of action was 7 days. The improvement way is as follows: Decreased abnormal increase of GABA and GB1 in the DRN further mediated synaptic inhibition and increased 5-HT level in the DRN, leading to increased 5-HT levels in the PFC, hypothalamus, and hippocampus. Therefore, GB1-mediated GABA in the DRN could regulate 5-HT levels in these brain regions, which may be one of the ways by which BXD and SY treat AO and AI, respectively.

Abbreviations

ABT: Aggressive behavior test; AI: Anger-in; AO: Anger-out; BXD: Baixiangdan Capsule; DRN: Dorsal raphe nucleus; GB1: GABABR1; GB2: GABABR2; OFT: Open field test; PFC: Prefrontal cortex; 5-HT: Serotonin; SY: Shuyu Capsule; SPT: Sucrose preference test.