大鼠海马神经元自发放电对皮下注射福尔马林的反应

RESPONSES OF HIPPOCAMPAL NEURON DISCHARGES TO SUBCUTANEOUS FORMALIN INJECTION IN THE RAT

采用玻璃微电极细胞外记录法，观察了清醒完整大鼠海马神经元自发放电对皮下注射福尔马林的反应。结呆显示，在海马CA2／CA3区可记录到痛兴奋、痛抑制和非痛敏三种神经元。同侧前爪皮下注射福尔马林后，痛兴奋神经元的自发放电显著增多，而痛抑制神经元的自发放电显著减少，这种变化在给予福尔马林后30min左右达到最大值，在60min左右恢复到对照水平；但在给予福尔马林后，非痛敏神经元的自发放电无明显变化。以上实验结果提供了在福尔马林痛模型中，海马在痛感受或痛反应过程中发挥一定作用的电生理证据。

To investigate the electrophysi-ological characteristics of hippocampal neurons in formalin pain model, we studied the responses of spontaneous activity of neurons in hippocampus to the subcutaneous injection of formalin with extracel-lular microelectrode recording technique in intact awake rats. Three types of neurons were recorded in the CA2/CA3, namely the pain excitatory neu-ron, the pain inhabitory neuron and the pain non-sensitive neuron respectively- After formalin injec-tion, the discharRe frequency of the pain excitatory neuron significantly increased, while that of the pain inhabitory neuron significantly decreased, reaching their maxima at about 30min, and then returning gradually to preinjection values at about 60min. In contrast to those of the two kinds of neurons, no significant changes in the frequency of discharge of the pain non-sensitive neuron were found within 6omin after formalin injection. The results imply that both the pain excitatory neuron and the pain in-habitory neuron may play a role in nociception or Dain modulation in the formalin pain model.