〔Abstract〕 Objective Microinjection of NG2 cell antibodies(NG2-Ab),the effect of NG2 cells on the change of γ-aminobutyric acid( GABA) and glutamate( Glu) transmitter content in the raphe nucleus of rats were studied by microdialysis to investigate the interaction between 5-hydroxytryptamine( 5-HT) and NG2 in the raphe nucleus.Methods Seventy rats were randomly divided into normal group,control group,NG2-AB group,PCPA group,5-HT group,PCPA + NG2-Ab group and 5-HT + NG2-Ab group. Normal group did not receive any treatment. The other groups were microinjected with saline( control group),NG2-Ab、PCPA、5-HT、PCPA + NG2-Ab and 5-HT +NG2-Ab,into the middle suture nucleus. The corresponded drugs were microinjected into the raphe nucleus. Microdialysis was used to collect extracellular fluid of the raphe nucleus 20,40,60,80,100 and 120 min after injection,respectively. High performance liquid chromatography( HPLC) was used to analyze the content changes of GABA and Glu in the microdialysate in corresponding time. Results Compared with the control group,NG2-Ab group decreased the content of GABA and Glu( P<0. 05),and the difference was statistically significant; PCPA group decreased content of GABA and increased Glu( P<0. 05). 5-HT group content increased of GABA( P<0. 05) and decreased Glu( P<0. 01). Compared with the PCPA group,there was no statistical difference in GABA content after PCPA + NG2-Ab injection,while Glu content decreased( P<0. 05). Compared with the 5-HT group,there was no statistical difference in GABA content after 5-HT + NG2-Ab injection in the raphe nucleus,while Glu content decreased( P<0. 05). Conclusion The content changes of GABA and Glu in raphe nucleus is affected by the inhibition of excitability of NG2 cells. The regulation effect of NG2 on Glu content is related to the synthesis of 5-HT,but its regulation effect on GABA content may not be directly related to the synthesis of 5-HT.