Spinal release of the amino acids with a time course in a rat model of postoperative pain.
Spinal release of the amino acids with a time course in a rat model of postoperative pain.
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DOI：
10.1097/00029330-200711020-00006
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发表时间：
2007-11
影响因子：
6.1
通讯作者：
Yun Wang;Y. Yue;Lin Shi;Anshi Wu;Chun-sheng Feng;C. Ni
中科院分区：
文献类型：
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作者：
Yun Wang;Y. Yue;Lin Shi;Anshi Wu;Chun-sheng Feng;C. Ni
背景术后疼痛的机制尚不清楚。兴奋性和抑制性氨基酸神经递质在脊髓背角疼痛的传递和调节中发挥重要作用。本研究旨在探讨术后疼痛时脊髓兴奋性和抑制性氨基酸释放的变化，为术后疼痛管理提供新的理论依据。方法将Loop微透析导管经寰枕膜植入16只健康Sprague-Dawley大鼠蛛网膜下。恢复5天后，将所有无神经功能缺损的大鼠分为两组，A组和B组。连接微透析管，每只大鼠冲洗1小时后收集25 μ l微透析液样品用于基线值。在1.2%异氟醚下，在A组大鼠的右后爪中进行足底切口。B组仅用1.2%异氟醚麻醉，麻醉时间相同。两组均于手术后3 h、1d、2d、3d采集微透析液标本（B组为异氟醚麻醉）。还在上述时间点评估了累积疼痛评分。使用高效液相色谱法检测微透析液样品中的氨基酸。结果A组中，天冬氨酸和谷氨酸的释放在切开后3 h显著高于基线值，甘氨酸的释放在切开后1d显著高于基线值（P0.05）。术后3 h A组天门冬氨酸和谷氨酸的释放量明显高于B组（P < 0.01）。术后第1天A组甘氨酸释放量较B组显著增加（P < 0.01）。术后3 h、1d、2d疼痛积分A组明显高于B组（P < 0.01）。结论：在大鼠切口疼痛模型中，兴奋性氨基酸的释放发生在术后疼痛的早期阶段，可能不参与疼痛的维持。抑制性甘氨酸的释放滞后于兴奋性氨基酸。抑制性甘氨酸释放的含义仍有待进一步确定。
BACKGROUND The mechanisms underlying postoperative pain remain unclear. Neurotransmitters of excitatory and inhibitory amino acids play an important role in the transmission and modulation of pain in the spinal dorsal horn. This study aimed to investigate the changes of release of excitatory and inhibitory amino acids in the spinal cord during postoperative pain and to provide a novel theoretical basis for postoperative pain management. METHODS Loop microdialysis catheters were implanted subarachnoidally via the atlanto-occipital membrane in 16 healthy Sprague-Dawley rats. All rats without neural deficits were divided into two groups, Group A and Group B, following 5 days of recovery. The tubes for microdialysis were connected and 25 microl microdialysate sample for baseline value was collected after one-hour washout in each rat. A plantar incision in the right hind paws of rats in Group A were performed under 1.2% isoflurane. All rats in Group B were only anesthetized by 1.2% isoflurane for the same duration. The microdialysate samples were collected at 3 hours, 1 day, 2 days and 3 days after the incision (or isoflurane anesthesia in Group B) in both groups. The cumulative pain scores were also assessed at the above time-points. The amino acids in the microdialysate samples were tested using high performance liquid chromatography. RESULTS Within Group A, the release of aspartate and glutamate at 3 hours after the incision was significantly higher than the baseline values and the release of glycine at 1 day after the incision significantly increased compared with the baseline values (P 0.05). The release of aspartate and glutamate at 3 hours after the incision in Group A was significantly higher than that in Group B (P < 0.01). The release of glycine at 1 day after the incision in Group A significantly increased compared with Group B (P < 0.01). The cumulative pain scores at 3 hours, 1 day and 2 days after the incision in Group A were significantly higher than those in Group B (P < 0.01). CONCLUSIONS The release of the excitatory amino acids occurs in the early phase of postoperative pain and might not be involved in the maintenance of pain in a rat model of incision pain. The release of inhibitory glycine lagged behind the excitatory amino acids. The implication of inhibitory glycine release remained to be established further.