[Protective effects of liquid extract of Lishi No.5 formula against excitatory amino acid damage of neurons].
OBJECTIVE
To investigate the effect of liquid extract of Lishi No.5 formula in protecting the neurons from excitatory amino acid injury.


METHODS
Cultured neonatal SD rat hippocampal neurons were treated with 300 micromol/L NMDA and 5 micromol/L glycine for 10 min, and the conditioned culture medium was replaced by normal culture medium. After cell culture for 18 h, MTT assay and Hoechst33258 staining were performed to examine the cell survival rate and cell apoptosis, respectively. Intracellular free calcium concentration was assayed by image analysis of the calcium signals with confocal microscope and Fluo-3/AM indicator.


RESULTS
The survival rate of the cultured cell was significantly decreased in response to treatment with 300 micromol/L NMDA and 5 micromol/L glycine, but the effects were obviously reversed by treatment with 0.5 mg/ml liquid extract from Lishi No.5 formula. Intracellular free calcium concentration was significantly increased by 10 micromol/L NMDA, which was remarkably inhibited by the liquid extract. The effects of NMDA on intracellular free calcium was abolished by pretreatment of the cells with MK-801 for 10 min, whereas the liquid extract significantly lowered the antagonizing effect of MK-801.


CONCLUSIONS
Lishi No.5 formula protects the neurons from toxicity by excitatory amino acids possibly by alleviating intracellular free calcium overload induced by these amino acids.
Hu
De-hui
DH
Department of Physiology, Southern Medical University, Guangzhou 510515, China.
Yang
Jian-ming
JM
Chang
Quan-zhong
QZ
Li
Sheng-hai
SH
Li
Zi-zhong
ZZ
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018846:Excitatory Amino Acids / Q000633:toxicity*; D006624:Hippocampus / Q000166:cytology*; D016202:N-Methylaspartate / Q000378:metabolism; D009474:Neurons / Q000166:cytology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004365:Drugs, Chinese Herbal; D018691:Excitatory Amino Acid Antagonists; D018846:Excitatory Amino Acids; D018696:Neuroprotective Agents; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D002118:Calcium