Protective effect of gui zhi (Ramulus Cinnamomi) on abnormal levels of four amino acid neurotransmitters by chronically ma huang (Herb Ephedra) intoxicated prefrontal cortex in rats treated with a ma huang-gui zhi herb pair.

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE The Herb Ephedra (Ma Huang in Chinese)-Ramulus Cinnamomi (Gui Zhi in Chinese) herb pair is a classic traditional Chinese herb pair used to treat asthma, nose and lung congestion, and fever with anhidrosis. In previous study, we found that chronic administration of ma huang induced obvious neurodegeneration in rat brains, with the prefrontal cortex showing the greatest effect. Gui zhi decreased hyperactivity produced by repeated ma huang administration, and attenuated oxidative stress in rat prefrontal cortex induced by ma huang. AIM OF THE STUDY The study was aimed to investigate the protective effect of gui zhi on ma huang-induced abnormal levels of four amino acid neurotransmitters in rat prefrontal cortex. MATERIALS AND METHODS: All ma huang and ma huang-gui zhi herb pair extracts were prepared using methods of traditional Chinese medicine and were normalized based on the ephedrine content. Two-month-old male Sprague-Dawley rats (6 rats/group) were administered ma huang or ma huang-gui zhi herb pair extracts for 1, 3, 5 or 7 days (ephedrine = 48 mg/kg). The contents of ephedrine, glutamate (Glu), aspartic acid (Asp), glycine (Gly), and gamma-aminobutyric acid (GABA) in the prefrontal cortex were determined using ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) at 0.5, 1.0, 5.0 h after administration. RESULTS: Ma huang significantly enhanced the levels of GABA, Gly, Glu and Asp in the prefrontal cortex, while gui zhi partially abolished the effects. CONCLUSIONS: Ma huang-induced neurotoxicity may be associated with its effects on amino acid neurotransmitters. Gui zhi is a promising neuroprotective agent against for ma huang-induced neurotoxicity. The information presented in this study will help supplement the available data for future ma huang-gui zhi herb pair compatibility studies.