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不同型態短期電刺激於脊髓橫切動物的雷射誘發背柱電位之立即效果-初步報告

The Temporal Effect of Different Modes of Electrical Nerve Stimulation on Laser Evoked Dorsal Column Potentials in Spinal Rat-Preliminary Result

Abstracts


本研究的主要目的在於探討不同型態電刺激(單一刺激及連續刺激),及不同強度之電刺激是否在脊髓產生立即的抑制效果。實驗Sprague-Dawley rats接受去大腦及脊髓橫切手術後,分別接受單一或是連續不同強度的電刺激,記錄雷射誘發脊髓電位(Laser Evoked Dorsal column Potentials; LEDCPS)變化作為客機的測量指標。結果顯示單一的刺激後皆無明顯的抑制作用,而連續的刺激1-3秒以上,則可產生有意義的抑制作用,高頻(100Hz)、低強度(5倍於閥值)的強度連續刺激l秒可產生立即的部份抑制但不能持續,低頻(2Hz)、高強度(100-200倍於閥值)的刺激則可產生立即且較強的抑制作用,這個抑制作用亦可在刺激結束後維持數5-20秒之久。本實驗以脊髓化動物為模型除去脊髓以上之中樞(supraspinal center)的影響,探討電刺激的脊髓機轉。結果顯示,電刺激可在脊髓部位產生抑制作用。而此作用與刺激的頻率及強度有關。

Keywords

電刺激 止痛 雷射 誘發電位

Parallel abstracts


The aim of this investigation is to determine the temporal effect of different modes (frequency and intensity) of electrical nerve stimulation. Laser-evoked dorsal column potentials (LEDCP) are used as an objective measurement to study the effect of peripheral stimulation in spinal cord. The experimental animals were made a spinal transection at the T7-8 level. Laser stimulation was applied to the plan- tar surface of the foot. Four different modes of electrical nerve stimulation were applied to the common peroneal nerve be protected cuff electrodes wrapped around the nerve. Single stimulation with low intesity (5 times threshold; LIS) and single stimulation with high intensity (100-200 times threshold; HI-S) were applied for only one sqaure wave stimulation with duration of 0.5 msec. High frequency (100Hz)-low intensity (5 times threshold) stimulation (HFLI), and low frequency (2Hz)-high intensity (200 times threshold) stimulation (LFHI) were applied as a continuous train of square wave stimulation lasting for 1 sec and 5 secs respectively. All these four modes of electrical stimulation were applied through a protected cuff electrode. Each mode of stimulation preceedes the testing laser stimulation at different intervals (0, 50, 100, 250, 500, 1000) at different trials. Single stimulation, neither low intensity (LI-S) nor high intensity (HI-S) demonstrated significant suppression effect on LEDCPs. FIFLI elicits partial inhibition on the LEDCPs at the interval of 0 msec. LFHI elicits more dramatic inhibition at a wider range of intervals (about a few secs). Our results demonstrate different modes of electrical stimulation with a few seconds of duration produced fast onset (within msecs) and short lasting (within seconds) of inhibition in the spinal cord. The significance of this study is the demonstration of the suppression of the spinal activity that is related to the intensity and frequency of the electrical stimulation.

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