Ginsenoside Rg1 activated CaMKIIα mediated extracellular signal-regulated kinase/mitogen activated protein kinase signaling pathway
Aim: We carried out this study to investigate the effect of ginsenoside Rg1 on the extracellular signal-regulated kinase/mitogen activated protein kinase (ERK/ MAPK) pathway for understanding its effect on synaptic platicity. Methods: Western blotting and immunostaining were used to examine the phosphorylation of ERK1/2, CaMKIIα and cAMP response element binding protein (CREB) in PC 12 cells and synaptosomes. The confocal microscopy and fluorescent indicator Fluo-3 was applied to observe the intracellular calcium ion flux. Results: The phosphorylation of ERK1/2 in PC 12 cells and synaptosomes incubated with Rg1 was increased and reached maximum at 4 min. Rg1 also promoted the transient enhancement of upstream calcium ion and activated CaMKIIot, which reached maximum at 2 min. CREB, the downstream protein, was phosphorylat-ed within 8 min in PC 12 cells after being incubated with Rg1. Moreover, KN93 partially inhibited the activation of ERK1/2, and PD98059 also partially blocked the phosphorylation of CREB. Conclusions: Rg1 activated ERK/MAPK pathway by CaMKIIα, and the activation of CREB was not only dependent on ERK induced by Rg1, which may provide an explanation for the effect of Rg1 on long-term potentiation.
Document Type: Research Article
Affiliations: Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
Publication date: 2008-09-01