Koyanagi I, Tator C H
Canadian Paraplegic Association Spinal Cord Injury Research Laboratory, Toronto Hospital, Ontario, Canada.
Electroencephalogr Clin Neurophysiol. 1996 Dec;101(6):534-42. doi: 10.1016/s0013-4694(96)96007-5.
The purpose of this study was to standardize the method of spinal cord monitoring with evoked potentials in the rat. Seventeen male Wistar rats were anesthetized with alpha-chloralose and urethane. Somatosensory evoked potential (SEP) and cerebellar evoked potential (CEP) following sciatic nerve stimulation were mapped at different time points after induction of anesthesia. SEP peaks at latencies of 13-18 ms (P13, N18) were localized to an extremely small area over the sensory cortex. In contrasts, a negative peak of the SEP at 11 ms (N11) and the CEP were widely distributed over the cerebral or cerebellar surface. Anesthesia significantly influenced the cortical components of the SEP. In 10 rats, MEP or posterior fossa evoked potential (PFEP) following stimulation of the sensorimotor or cerebellar cortices respectively, were recorded at T9. Stimulation of different points produced little change on the waveforms of the MEP or PFEP. Successive recordings of MEP and SEP revealed that the P13-N18 complex of the SEP was markedly suppressed after MEP recordings were made. In conclusion, this study identified several factors which alter SEP waveforms in the rat including location of recording, anesthesia and sequence with respect to MEP recording. MEP by stimulation of the same sensory cortex as SEP recordings should not be used for concurrent monitoring, since cortical stimulation will change the waveforms of the SEP.
本研究的目的是规范大鼠诱发电位脊髓监测方法。17只雄性Wistar大鼠用α-氯醛糖和乌拉坦麻醉。在麻醉诱导后的不同时间点，绘制坐骨神经刺激后的体感诱发电位（SEP）和小脑诱发电位（CEP）。潜伏期为13 - 18毫秒的SEP波峰（P13、N18）定位于感觉皮质上一个极小的区域。相比之下，11毫秒时SEP的负向波峰（N11）和CEP广泛分布于大脑或小脑表面。麻醉对SEP的皮质成分有显著影响。在10只大鼠中，分别在T9记录了刺激感觉运动皮质或小脑皮质后的运动诱发电位（MEP）或后颅窝诱发电位（PFEP）。刺激不同点对MEP或PFEP的波形影响很小。MEP和SEP的连续记录显示，在记录MEP后，SEP的P13 - N18复合波明显受到抑制。总之，本研究确定了几个会改变大鼠SEP波形的因素，包括记录位置、麻醉以及与MEP记录的顺序。由于皮质刺激会改变SEP的波形，因此不应使用与SEP记录相同的感觉皮质刺激来同时监测MEP。
