5-HT对大鼠脊髓背角WDR神经元伤害性电刺激诱发放电的影响

Effects of 5-hydroxytryptamine on nociceptive reactions of WDR neurons in the spinal dorsal horn of rats

目的 观察 5 羟色胺 (5 HT)对大鼠脊髓背角广域 (WDR)神经元伤害性电刺激诱发放电的影响。方法 对完整SD雄性大鼠模型 ,采用微电极细胞外记录方法 ,观察脊髓表面使用 5 HT前后脊髓背角WDR神经元对伤害性电刺激诱发放电频率变化 ,并分析其作用机制。结果 不同剂量 5 HT(12 .5 μg/ 4 μl,2 5 μg/ 4 μl,5 0 μg/ 4 μl)应用后 ,脊髓背角WDR神经元伤害性放电频率显著降低 ,且降低幅度随 5 HT剂量的增加而增大 ;5 HT拮抗剂美西麦角 (methysergide)对 5 HT具有拮抗效应。结论 5 HT对大鼠脊髓背角WDR神经元伤害性电刺激诱发放电具有剂量依赖性抑制作用 ,此作用由脊髓内 5 HT受体介导 ;5

Objective To evaluate the effects of 5-HT on noxiously-evoked activities of wide dynamic range(WDR) neurons in the spinal dorsal horn of intact male SD rats.Methods Microelectrode extracellular recordings were used to observe the WDR neuron discharge frequency changes before and after the use of different doses of 5-HT(12.5 μg/4 μl, 25 μg/4 μl, 50 μg/4 μl) on the animal hind paw. The mechanism of the antinociceptive effect of 5-HT was investigated by use of methysergide and the antagonist of 5-HT receptor. Results ① The unit discharge frequency of WDR neurons was significantly decreased after noxious stimulation at different doses of 5-HT; ② The effects of 5-HT on the noxious stimulation evoked activity of WDR neurons were partially reversed by methysergide. Conclusion 5-HT can dose-dependently suppress noxiously-evoked activity of WDR neurons in dorsal horn, which is likely to be mediated by 5-HT receptors. The tonic activity of 5-HT in spiual cord of rats is detected.