5-羟色胺重摄取过程的机制  

The Mechanism for Serotonine Re-uptak by Heterologous Expressed Human Serotonine Transporter in Xenopus Oocyte

作　　者：李慈珍[1] 杨智昉[1] 王艺颖[1] 张野[1] 郑燕倩[1] 刘远谋[1] 王红卫[1] 

机构地区：[1]上海交通大学医学院生理教研室,上海200025

出　　处：《细胞生物学杂志》2006年第6期917-922,共6页Chinese Journal of Cell Biology

基　　金：上海市科委重点资助项目(No.03JC14034;No.06JC14045);上海教委第四期重点学科资助项目(No.ZDXK2001)~~

摘　　要：将重组质粒pOTV-hSERT(oocytetranscriptionvector)中的人5-羟色胺转运体(hSERT)cDNA转录合成cRNA,通过显微注射技术注入爪蟾卵母细胞,建立hSERT异体表达模型,用电压钳技术测定其转运功能,研究hSERT重摄取的调控因素。胞外5-羟色胺(5-HT)灌流液引起内向转运电流,可被hSERT特异阻断剂去甲丙米嗪(desipramine)所阻断。该电流大小随测试电位的变化而改变,膜电位愈负,转运电流愈大。灌流液无钠或无氯时,转运电流分别减小(89.6±1.4)%和(51.7±1.5)%,表明胞外钠、氯离子为转运过程的必需条件。胞外5-HT浓度变化时,转运电流呈剂量依赖性,并有饱和现象。提高胞内5-HT浓度至胞外的20或40倍时,并不影响转运过程。因此,5-HT的重摄取与胞外Na+、Cl-离子联合转运有关,胞内5-HT浓度并不影响转运电流的大小,细胞膜电位的变化对转运过程有快速调控作用。cRNA of SERT was transcribed from cDNA, which was cloned in the pOTV vector. Oocytes of Xenopus laevis were injected with transcribed cRNA in vivo and turned to a heterologous expression model （human serotonin transporter, hSERT） in 5-6 days. With voltage clamp technique in recording the current induced by 5-HT, we tested the function of the expressed 5-HT transporter and studied factors which influence the reuptake of hSERT. When the cell membrane potential was held at -60 mV and perfused with Ringer＇s solution containing 5-HT, a steady inward current appeared and was almost completely inhibited by specific 5-HT transporter blocker, Desipramine, which demonstrated that it was 5-HT-induced current. The 5-HT-induced current varied with holding potentials or voltages in step protocol. The more negative of the clamping voltage, the bigger of the 5-HT-currents. The results from the experiments with 0 mmol/L Na^＋ or 0 mmol/L Cl^- in Ringer solution indicated that transporting of 5-HT required Na^＋ and Cl^- ion in extra-cellular solution and the influences of Na^＋ and Cl^- ion on transporting were different, for with 0 mmol/L Na^＋ or 0 mmol/L Cl^- the currents were reduced by （89.6＋ 1.4）% and （51.7＋1.5）% respectively. As the concentration of 5-HT in the perfusing Ringer＇s solution increased from 0.1 to 15 lxmol/L, the current augmented accordingly until it was saturated. Injection of 5-HT into the Oocyte making the intracellular concentration of 5-HT increased to about 20 or 40 folders, the 5-HT-induced current was not changed in spite of the changes of intracellular concentrations of 5-HT. Conclusion： Na^＋ ion and Cl^- ion are co-transported with 5-HT. The cell membrane potential may influence the 5-HT-induced current fulfilling a rapid regulation for re- uptake of 5-HT. Changing the intracellular concentration of 5-HT does not influence the amplitude of transporter current.

关 键 词：5羟色胺转运体 卵母细胞 异体表达 电压钳 

分 类 号：Q42[生物学—神经生物学]