Dowman R, Rosenfeld J P
Brain Res. 1985 May 6;333(2):201-12. doi: 10.1016/0006-8993(85)91573-2.
The aim of this experiment was to investigate possible endogenous opioid modulation of innocuous somatosensory activity. Somatosensory activity was measured by recording cortical somatosensory evoked potential (SEP) and reflex movement amplitude evoked by innocuous electrical stimulation of the spinal trigeminal tract in awake rats. Putative endogenous opioid activity was blocked using the opiate antagonist naloxone (1 mg/kg). The amplitude of midlatency SEP components (14-50 ms latency) increased following administration of naloxone and repeated stimulus presentations. The amplitude of these components decreased following administration of the opiate agonist morphine (3 mg/kg). An early cortical component (10 ms latency) habituated following the administration of saline but did not habituate following naloxone. Naloxone also enhanced habituation of the late SEP components (60-120 ms latency) and reflex movement evoked at higher stimulus intensities. Morphine decreased the amplitude of the early cortical component but had no consistent effect on the amplitude of the late SEP components.
本实验的目的是研究内源性阿片类物质对无害体感活动的可能调节作用。通过记录清醒大鼠脊髓三叉神经束无害电刺激诱发的皮层体感诱发电位（SEP）和反射运动幅度来测量体感活动。使用阿片类拮抗剂纳洛酮（1毫克/千克）阻断假定的内源性阿片类活性。给予纳洛酮并重复刺激呈现后，中潜伏期SEP成分（潜伏期14 - 50毫秒）的幅度增加。给予阿片类激动剂吗啡（3毫克/千克）后，这些成分的幅度降低。给予生理盐水后，早期皮层成分（潜伏期10毫秒）出现习惯化，但给予纳洛酮后未出现习惯化。纳洛酮还增强了晚期SEP成分（潜伏期60 - 120毫秒）和较高刺激强度诱发的反射运动的习惯化。吗啡降低了早期皮层成分的幅度，但对晚期SEP成分的幅度没有一致的影响。
