Relationship between thalamocortical glutamate and neuronal activity in mice with sleep disorders induced by neuropathic pain / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between thalamocortical glutamate and neuronal activity in mice with neuropathic pain-induced sleep disorders.Methods:SPF healthy male C57BL/6 mice, aged 6-8 weeks, weighing 15-25 g, were divided into 2 groups ( n=14 each) using a random number table method: sham operation group (Sham group) and neuropathic pain group (CCI group). Neuropathic pain was induced by chronic constrictive injury (CCI). The animals were anesthetized with intraperitoneal 10% chloral hydrate 3 ml/kg.The right sciatic nerve was exposed and 4 ligatures were placed on the sciatic nerve at 1 mm intervals.The mechanical paw withdrawal threshold and thermal paw withdrawal latency on the operated side were measured at 1 day before CCI (T 0) and 3, 5, 7, 14 and 21 days after CCI (T 1-5). Electroencephalogram recording electrodes were stereotaxically implanted in visual cortex at T 3, and electroencephalogram were monitored for 6 h, the percentages of non-rapid eye movement, rapid eye movement and wakefulness in the total time were calculated.Microwire electrodes were implanted epidurally over the ventral posterior (VP) nucleus of the thalamus and primary somatosensory cortex (S1) using a brain stereotaxic apparatus at T 3, and the data acquisition system was used to record field potentials at T 4, the percentage of power of each wave was calculated, and the coherence of the field potentials of VP and S1 was simultaneously evaluated.The mice were sacrificed at T 4, brain tissues were collected, and proton nuclear magnetic resonance spectroscopy was used to determine the level of neurotransmitter in the thalamus and cortex. Results:Compared with group Sham, the mechanical paw withdrawal threshold was significantly decreased and thermal paw withdrawal latency was shortened at T 1-5, the percentage of non-rapid eye movement time was decreased, the percentage of wakefulness time was increased, the percentage of &delta; wave power in the VP area was decreased, the percentage of &delta; wave power in the VP and S1 areas was increased, and the coherence of the field potentials of VP-S1 was increased in the frequency range of &delta; wave (1-4 Hz) and α wave (8-14 Hz), and the levels of glutamate, glutamine and glutamate-glutamine in the thalamus and cortex were increased in group CCI ( P<0.05). Conclusions:Neuropathic pain-induced sleep disturbance is related to increased thalamocortical glutamate levels, resulting in changes in the electrical activity of thalamocortical neurons of mice.