腺苷对大鼠离体脊髓运动神经元突触传递的影响  

Effects of adenosine on synaptic transmissions in rat spinal cord motoneuron in vitro

作　　者：刘静 汪萌芽[1] LIU Jing;WANG Mengya(Cell Electrophysiology Laboratory,Wannan Medical College,Wuhu 241002,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》2023年第6期511-515,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:观察腺苷对新生大鼠离体脊髓运动神经元(MN)突触传递,特别是脊髓内在通路和下行激活通路的影响。方法:选取新生SD大鼠(8~14 d)制备脊髓横切片,应用离体脊髓MN细胞内记录技术,记录电刺激(单脉冲,波宽0.1~0.3 ms,10次/分钟,15~100 V)同侧腹外侧索(iVLF)和同侧中央管周围区(iPCC)在MN诱发的兴奋性突触后电位(EPSP),即iVLF-EPSP和iPCC-EPSP,灌流50μmol/L腺苷,观察其对脊髓MN iVLF-EPSP和iPCC-EPSP的影响。结果:①在10个稳定记录的MN,灌流50μmol/L腺苷15 min,使MN去极化(P<0.01)并伴随膜电阻增大(P<0.05),AP幅度减小(P<0.01)。②在5个记录到自发放电的MN,灌流50μmol/L腺苷15 min,降低MN的自发放电频率(P<0.01)。③在8个MN,灌流50μmol/L腺苷15 min,可观察到iVLF-EPSP和iPCC-EPSP的幅度、曲线下面积均减小(P<0.05)。表观受体动力学分析显示iVLF-EPSP和iPCC-EPSP的表观结合速率常数K 1、表观解离速率常数K 2和表观平衡解离常数K T均无明显改变(P>0.05)。④在6个MN记录到iVLF电刺激诱发的iVLF-EPSP,给予10、50、250μmol/L腺苷各累积灌流15 min,可观察到浓度依赖性减小iVLF-EPSP的幅度(P<0.01);在5个MN记录到iPCC电刺激诱发的iPCC-EPSP,给予10、50、250μmol/L腺苷各累积灌流15 min,可观察到浓度依赖性减小iPCC-EPSP的幅度(P<0.01)。结论:腺苷可以浓度依赖性通过抑制脊髓内在调控通路和下行激活通路向MN的突触传递而调控脊髓运动控制的输出。Objective:To observe the effects of adenosine on synaptic transmissions,especially mediated by the spinal intrinsic regulation pathway and descending activation pathway of motoneuron(MN)in spinal cord slices.Methods:Spinal cord slices were prepared from neonatal SD rats(8-14 days old),and the ipsilateral ventrolateral funiculus(iVLF)and ipsilateral pericentral canal(iPCC)were electrically stimulated(single pulse,0.1-0.3 ms,10 times/min,voltage 15-100 V)to induce excitatory postsynaptic potential(EPSP,iVLF-EPSP and iPCC-EPSP)in MN.Adenosine at required concentration was perfused and the effect on spinal MN iVLF-EPSP and iPCC-EPSP was observed.Results:①In 10 MN,perfusion of 50μmol/L adenosine for 15 min resulted in depolarization of MN with increased membrane resistance(P<0.01 or P<0.05),and reduced the amplitude of AP(P<0.01);②In 5 MN,bath of 50μmol/L adenosine for 15 minutes led to reduced frequency of spontaneous spike discharges(P<0.01);③In 8 MN,after perfusing 50μmol/L adenosine for 15 minutes,a decrease in amplitude and area under curve of iVLF-EPSP and iPCC-EPSP was observed(P<0.05).The apparent association rate constant(K 1),apparent dissociation rate constant(K 2)and apparent equilibrium dissociation constant(K T)of iVLF-EPSP and iPCC-EPSP were not significantly changed by bathing 50μmol/L adenosine for 15 minutes(n=7,P>0.05);④In 6 MN with iVLF-EPSP,the amplitudes(P<0.01)of iVLF-EPSP were concentration-dependently decreased after gradient perfusion with 10,50 and 250μmol/L adenosine for 15 minutes.In the 5 MN with iPCC-EPSP,the amplitudes of iPCC-EPSP were concentration-dependently decreased after stepped perfusion with 10,50 and 250μmol/L adenosine for 15 minutes(P<0.01).Conclusion:Adenosine may concentration-dependently inhibit synaptic transmissions of spinal intrinsic regulatory pathway and descending activation pathway to MN,thereby regulating the output of spinal cord motor control.

关 键 词：腺苷 脊髓 运动神经元 兴奋性突触后电位 下行激活 中央管周围区 

分 类 号：R651.2[医药卫生—外科学] R-332[医药卫生—临床医学]