Ⅰ组代谢型谷氨酸受体激活调制脊髓运动神经元的下行激活  

Activation of group Ⅰ metabotropic glutamate receptors modulates descending activation of spinal cord motoneurons

作　　者：郑勇[1] 汪萌芽[1] 

机构地区：[1]皖南医学院细胞电生理研究室

出　　处：《中国临床药理学与治疗学》2011年第12期1374-1378,共5页Chinese Journal of Clinical Pharmacology and Therapeutics

基　　金：安徽省自然科学基金(090413084)

摘　　要：目的:探讨I组代谢型谷氨酸受体(mGluRs)激活对离体脊髓运动神经元(MN)下行激活的调制作用。方法:应用新生大鼠(7～14d)脊髓切片MN细胞内记录技术,记录脊髓同侧腹外侧索(iVLF)电刺激诱发的兴奋性突触后电位(EPSP,即iVLF-EPSP),观察I组mGluRs激动剂(S)-3,5-二羟基苯基甘氨酸(DHPG)对MN膜电学特性及iVLF-EPSP的影响。结果:对脊髓切片灌流DHPG(5μmol/L),能使MN膜去极化(n=7,P<0.01),缩短时间常数(n=7,P<0.05),并延长锋电位的半幅时程(n=5,P<0.05)。同时,给予DHPG(5～10μmol/L)能可逆性、浓度依赖性抑制iVLF-EPSP的幅度(n=7,P<0.01)。结论:DHPG对I组mGluRs的激活对离体脊髓MN的下行激活有抑制性调制作用。To evaluate the modulatory action of group I metabotropic glutamate receptors （mGluRs） on descending activation of spinal cord motoneurons （MNs） in vitro. METHODS： The intracellular recordings were made in MNs of spinal cord slices isolated from neonatal rats （7-14 days old）, and excitatory postsynaptic potential （EPSP） was evoked by ipsilateral ventrolateral funiculus （iVLF） stimulation, i.e. iVLFEPSP. By SUlderfusion of （S）-3, 5-dihydroxyphenylglycine hydrate （DHPG）, an ago- nist of group I mGluRs, the modulatory action was observed on the MN membrane electrical properties, as well as on the iVLFEPSP. RESULTS：Application of DHPG （5 /xmol/L） significantly depolarized the motoneuron membrane（n=7, P〈C0.01）, reduced time constant （n= 7, P（0.05）, and extended the halfwidth of the spike potential （n=5, P（0.05）. The amplitude of iVLFEPSPs in 7 tested MNs was reversibly and concentrationdependently suppressed by superfusion of DHPG （5- 10 μmol/L, P 〈 0.01）. CONCLUSION ： Activation of group Ⅰ mGluRs by DHPG may inhibit the descending activation of spinal cord MNs in vitro.

关 键 词：运动神经元 脊髓 代谢型谷氨酸受体 下行激活 (S)-3 5-二羟基苯基甘氨酸 

分 类 号：R965.2[医药卫生—药理学]