微透析法研究NG2细胞功能变化对大鼠中缝核兴奋性和抑制性递质含量的影响

The effect of NG2 cells function changes of inhibitory transmitter content in the raphe nucleus of rats studied by microdialysis

目的采用中缝核内微量注射NG2抗体(NG2-Ab),研究中缝核NG2细胞功能变化对γ-氨基丁酸(GABA)和谷氨酸(Glu)递质含量的影响,探讨中缝核中5-羟色胺(5-HT)与NG2细胞的相互作用对GABA和Glu递质含量变化的影响。方法70只大鼠随机分为正常组、对照组、NG2-Ab组、对氯基丙氨酸(PCPA)组、5-HT组、PCPA+NG2-Ab组和5-HT+NG2-Ab组。正常组不做任何处理,其他各组在中缝核内分别微量注射0.9%氯化钠溶液、NG2-Ab、PCPA、5-HT、PCPA+NG2-Ab及5-HT+NG2-Ab,采用微透析法收集注射完毕后20、40、60、80、100、120 min时间段内中缝核细胞外液,采用高效液相色谱法(HPLC)分析微透析液中GABA、Glu在相应时间内的含量及其变化。结果与对照组相比:NG2-Ab组GABA和Glu含量下降,差异有统计学意义(P<0.05);PCPA组GABA含量下降,Glu含量升高,差异有统计学意义(P<0.05);5-HT组GABA含量升高(P<0.05),Glu含量下降(P<0.01),差异有统计学意义。与PCPA组相比,PCPA+NG2-Ab组GABA在各时间段含量变化无统计学差异,Glu含量降低,差异有统计学意义(P<0.05)。与5-HT组相比,5-HT+NG2-Ab组GABA含量变化无统计学差异,Glu含量降低,差异有统计学意义(P<0.05)。结论NG2细胞的兴奋性受到抑制后影响大鼠中缝核内GABA和Glu含量的变化,Glu含量的变化与5-HT的合成有关,但GABA含量的变化与5-HT合成无直接关系。

Objective Microinjection of NG2 cell antibodies(NG2-Ab),the effect of NG2 cells on the change ofγ-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.