中文摘要：

目的：探讨胞外信号调节激酶（ERK Ⅰ／Ⅱ）在大鼠脊髓背角C-纤维诱发电位长时程增强（LTP）的诱导和维持中的作用。方法：细胞外记录技术在脊髓腰膨大部记录背角浅层神经元C-纤维诱发电位。结果：（1）MEK的选择性抑制剂PD98059（100μmol/L）或SL327（200μmol/L）时脊髓背角C-纤维诱发电位的基础电位没有影响，但可阻断脊髓背角LTP的诱导。（2）PD98059或SL327呈时间依赖性逆转脊髓背角LTP。在LTP诱导后15min．脊髓局部给予PD98059（100μmol/L）或SL327（200μmol/L）可完全逆转LTP。在LTP诱导后30min，单独给予PD98059或SL327，LTP的抑制率分别为62．5％与75．0％。但同样浓度的PD98059或SL327在LTP诱导后1h，均不能逆转业已建立的LTP。结论：脊髓背角ERK Ⅰ／Ⅱ的激活参与C-纤维诱发电位LTP的诱导和早期维持。

英文摘要：

AIM ： The role of external - signal regulated kinase Ⅰ/Ⅱ （ ERK Ⅰ/Ⅱ ） in the induction and maintenance of spinal long - term potentiation （LTP） is evaluated. METHODS： The C - fiber evoked field potentials were recorded at the superficial layers of spinal dorsal horn at the lumbar enlargement. RESULTS： （ 1 ） PD98059 （ 100 μmol/L） or SL327 （200 μmol/L） , a selective MEK inhibitor, completely blocked LTP induction when applied at 30 rain prior to tetanie stimulation. （2） PD98059 or SL327 reversed spinal LTP in a time - dependent manner. At 15 min after LTP induction, PD98059 （ 100 μmol/L） or S1327 （200 μmol/L） reversed LTP completely, and at 30 rain after LTP induction, the inhibitory rate of spinal LTP inhibited by PD98059 or SL327 was 62.5% and 75.0% , respectively. At 1 h after LTP induction, however, the same concentration of PD98059 or SL327 did not affect the spinal LTP. CONCLUSION： Activation of ERK Ⅰ/Ⅱ in spinal dorsal horn may be crucial for the induction and the early - phase maintenance of LTP of C - fiber evoked field potentials.