对侧腹外侧索强直刺激在脊髓运动神经元诱发的长时程增强

目的:探讨强直刺激对侧腹外侧索(cVLF),在脊髓运动神经元(MN)能否诱发突触传递的长时程可塑性变化。方法:应用新生大鼠脊髓切片MN细胞内记录技术,观察强直刺激cVLF前后,在MN诱发的兴奋性突触后电位(EP-SP,即cVLF-EPSP)的变化。结果:对cVLF施加强直刺激,有2个MNs的cVLF-EPSPs幅度增大达基础值的120%以上,且维持至少30 min,可被定义为长时程增强(LTP,即cVLF-LTP)。另外,在1个有cVLF-LTP的MN,同时观察到同侧背根刺激诱发的EPSP出现长时程增强。结论:通过强直刺激cVLF,在新生大鼠脊髓MN可诱发出突触传递的LTP,并可伴有异突触的LTP现象。

Long-term potentiation of synaptic transmis sion in motoneurons induced by tetanic stimu lation in contralateral ventrolateral funiculus of neonatal rat spinal cord in vitro

Objective:To explore whether long-term plasticity of synaptic transmission could be induced in motoneuron(MN) after tetanic stimulation of contralateral ventrolateral funiculus(cVLF) of spinal cord slices.Methods:The intracellular recordings were performed in MNs of neonatal rat spinal cord slices,with observing the change of excitatory postsynaptic potential(EPSP) induced by cVLF stimulus(i.e.cVLF-EPSP) in MN before and after tetanic stimulation of cVLF.Results:In 2 MNs,the amplitude of cVLF-EPSPs increased more than 120% of baseline and the increase lasted longer than 30 min after tetanic stimulation of cVLF,which could be referred to as long-term potentiation(LTP,i.e.cVLF-LTP).Moreover,in one MN with cVLF-LTP,the long-term enlargement of EPSP induced by ipsilateral dorsal root stimulation(iDR-EPSP) was observed as well.Conclusion: Longterm potentiation of contralateral descending activation in MN of neonatal rat spinal cord slices can be induced by tetanic stimulation of cVLF as well as concurrent heterosynaptic LTP of iDR-EPSP.