The electroencephalogram (EEG) provides an objective, neural correlate of consciousness. Opioid receptors modulate mammalian neuronal excitability, and this fact was used to characterize how opioids administered to mice alter EEG power and states of consciousness. The present study tested the hypothesis that antinociceptive doses of fentanyl, morphine, or buprenorphine differentially alter the EEG and states of sleep and wakefulness in adult, male C57BL/6J mice. Mice were anesthetized and implanted with telemeters that enabled wireless recordings of cortical EEG and electromyogram (EMG). After surgical recovery, EEG and EMG were used to objectively score states of consciousness as wakefulness, rapid eye movement (REM) sleep, or non-REM (NREM) sleep. Measures of EEG power (dB) were quantified as delta (0.5 to 4 Hz), theta (4 to 8 Hz), alpha (8 to 13 Hz), sigma (12 to 15 Hz), beta (13 to 30 Hz), and gamma (30 to 60 Hz). Compared to saline (control), fentanyl and morphine decreased NREM sleep, morphine eliminated REM sleep, and buprenorphine eliminated NREM sleep and REM sleep. Opioids significantly and differentially disrupted the temporal organization of sleep/wake states, altered specific EEG frequency bands, and caused dissociated states of consciousness. The results are discussed relative to the fact that opioids, pain, and sleep modulate interacting states of consciousness.

中文翻译：

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阿片类药物导致 C57BL/6J 小鼠的意识分离状态

脑电图 (EEG) 提供了一种客观的、神经相关的意识。阿片受体调节哺乳动物神经元的兴奋性，这一事实被用来表征给予小鼠的阿片类药物如何改变脑电图功率和意识状态。本研究验证了以下假设：芬太尼、吗啡或丁丙诺啡的镇痛剂量不同地改变成年雄性 C57BL/6J 小鼠的脑电图以及睡眠和清醒状态。小鼠被麻醉并植入遥测仪，可以无线记录皮质脑电图和肌电图（EMG）。手术恢复后，EEG 和 EMG 被用来客观地将意识状态评分为清醒、快速眼动 (REM) 睡眠或非快速眼动 (NREM) 睡眠。EEG 功率 (dB) 的测量值被量化为 delta (0.5 至 4 Hz)、theta (4 至 8 Hz)、alpha（8 到 13 Hz）、sigma（12 到 15 Hz）、beta（13 到 30 Hz）和 gamma（30 到 60 Hz）。与生理盐水（对照）相比，芬太尼和吗啡减少了 NREM 睡眠，吗啡消除了 REM 睡眠，丁丙诺啡消除了 NREM 睡眠和 REM 睡眠。阿片类药物显着和不同地破坏了睡眠/清醒状态的时间组织，改变了特定的脑电图频带，并导致意识分离状态。相对于阿片类药物、疼痛和睡眠调节相互作用的意识状态这一事实对结果进行了讨论。阿片类药物显着和不同地破坏了睡眠/清醒状态的时间组织，改变了特定的脑电图频带，并导致意识分离状态。相对于阿片类药物、疼痛和睡眠调节相互作用的意识状态这一事实对结果进行了讨论。阿片类药物显着和不同地破坏了睡眠/清醒状态的时间组织，改变了特定的脑电图频带，并导致意识分离状态。相对于阿片类药物、疼痛和睡眠调节相互作用的意识状态这一事实对结果进行了讨论。