2-AG对离体脊髓运动神经元外周传入突触传递的影响  

Effects of 2-AG on peripheral afferent synaptic transmission to spinal cord motoneuron in vitro

作　　者：周方云 汪萌芽[1] ZHOU Fangyun;WANG Mengya(Cell Electrophysiology Laboratory,Wannan Medical College,Wuhu 241002,Anhui,China)

机构地区：[1]皖南医学院细胞电生理研究室,安徽芜湖241002

出　　处：《皖南医学院学报》2024年第4期307-310,315,共5页Journal of Wannan Medical College

基　　金：国家自然科学基金项目(31271155)。

摘　　要：目的:探究2-花生四烯酸甘油(2-AG)如何影响新生大鼠离体脊髓运动神经元(MN)外周传入所诱发出的兴奋性突触后电位(iDR-EPSP)。方法:本研究使用8~14 d新生SD大鼠,制备400~500μm厚的脊髓横切片,通过脊髓MN细胞内记录技术,观察2-AG对电刺激同侧背根诱发iDR-EPSP的影响。结果:在11个MN灌流5μmol/L 2-AG 15 min,观察到伴随膜电阻增大的去极化反应(P<0.01)。在15个MN灌流5μmol/L 2-AG 15 min,观察到iDR-EPSP幅度和曲线下面积均减小(n=15,P<0.01)。在9个MN累积灌流1、5和25μmol/L 2-AG各15 min均可诱导去极化反应,浓度依赖性减小iDR-EPSP的幅度(P<0.01)和曲线下面积(P<0.05)。对17个灌流25μmol/L 2-AG 15 min的MN使用表观受体动力学方法进行分析,结果显示,25μmol/L的2-AG可降低iDR-EPSP的表观最大反应(V_(max))和表观解离速率常数(K_(2))(P<0.05),但表观结合速率常数(K_(1))与表观平衡解离常数(K T)改变无统计学意义(P>0.05)。结论:2-AG对离体脊髓MN外周传入兴奋性突触传递呈现浓度依赖性抑制效应。Objective:To investigate effects of 2-arachidonoylglycerol(2-AG,one of endocannabinoids)on the excitatory postsynaptic potential(iDR-EPSP)evoked by peripheral inputs in isolated spinal motorneuron(MN)of newborn rats in vitro.Methods:Neonatal SD rats(8-14 days old)were used to prepare the transverse spinal cord slices(400-500μm in thickness).The experiment was conducted using intracellular recording technique from spinal MN,aiming to observe the effect of 2-AG on the iDR-EPSP in MN evoked by electrical stimulation of ipsilateral dorsal roots.Results:In the 11 MN,perfusion of 5μmol/L 2-AG for 15 min induced a depolarizing response accompanied by an increase in membrane resistance(P<0.01).In the 15 MN,perfusion of 5μmol/L 2-AG for 15 min resulted in a decrease in both the amplitude and area under curve of iDR-EPSP(n=15,P<0.01).In another 9 MN,cumulative perfusion of 1,5,and 25μmol/L 2-AG for 15 min each induced depolarizing responses and concentration-dependently reduced iDR-EPSP amplitude(P<0.01)and area under curve(P<0.05).Apparent receptor kinetic analysis was performed on iDR-EPSP of 17 MN perfused with 25μmol/L 2-AG for 15 min,which demonstrated reduced apparent maximum response(V_(max))and apparent dissociation rate constant(K_(2))of iDR-EPSP(P<0.05),yet the difference was insignificant in the changes of apparent association rate constant(K_(1))and apparent equilibrium dissociation constant(K T)(P>0.05).Conclusion:2-AG can produce a concentration-dependent inhibitory effects on the peripheral afferent excitatory synaptic transmission to spinal cord MNs in vitro.

关 键 词：2-花生四烯酸甘油 脊髓 运动神经元 兴奋性突触后电位 

分 类 号：R-332[医药卫生] R338