Abstract: ObjectiveTo explore the effects of the serum of traditional Chinese medicine Nao Yi An on glutamate induced cell death in cultured hippocampal neurons of rat and the underlying mechanisms. MethodsHippocampal neurons were cultured. The excitatory amino acid induced toxicity on cultured neurons was investigated. The viability of injured neurons was determined with the measurement of Lactate dehydrogenase (LDH) activity. Mitogen activated protein kinase (MAPK) were determined by immunoprecipitation /kinase assays /western blot detection.ResultsThe serum of Nao Yi-An raised cell viability. The serum of Nao Yi-An upregulated the expression of extracellular regulated protein kinases(ERK) and downregulated the expression of c-Jun N terminal kinase/stress activited protein kinase(JNK) in cultured neurons. The serum of Nao Yi-An induced upregulation of ERK and its anti death action were prevented with the specific ERKs inhibitor PD98059. Conclusions Activation of ERK signaling together with inhibition of JNK signaling by Chinese medicine Nao Yi-An appears to be an important mechanism for its survival effects on cultured hippocampal neurons.

Key words: Nao Yi-An, serum pharmacology, excitatory amino acid, LDH, MAPK, cultured neurons, therapy of Traditional Chinese Medicine