PKC在成年大鼠脊髓背角C-纤维诱发电位长时程增强的诱导和维持中的作用

目的：探讨蛋白激酶C (PKC) 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) PKC的选择性抑制剂chelerythrine（200 μmol/L）或G 6983（100 μmol/L）对脊髓背角C-纤维诱发电位的基础电位没有影响，但可完全阻断脊髓背角LTP的诱导。(2) Chelerythrine或G 6983呈时间依赖性翻转脊髓背角LTP。在LTP 诱导后15 min，脊髓局部给予chelerythrine（200 μmol/L）后，LTP逐渐降低，于给药后70 min降至对照水平；而G 6983（100 μmol/L）产生同chelerythrine相似的效应，在用药后110 min，LTP降至对照水平。但同样浓度的chelerythrine或G 6983在LTP 诱导后3 h，均不能翻转业已建立的LTP。结论： PKC参与脊髓背角C-纤维诱发电位LTP的诱导和早期维持，而不影响晚期LTP的维持。

Protein kinase C is involved in the induction and early-phase maintenance of long-term potentiation of C-fiber evoked field potentials in spinal dorsal horn of adult rats

AIM: The role of protein kinase C (PKC) in the induction and maintenance of spinal long-term potentiation (LTP) was evaluated. METHODS: The C-fiber evoked field potentials were recorded at the superficial layers of spinal dorsal horn at the lumbar enlargement. RESULTS: (i) Chelerythrine （200 μmol/L） or G 6983 (100 μmol/L), a selective PKC inhibitor, completely blocked LTP induction. (ii) Chelerythrine or G 6983 reversed spinal LTP in a time-dependent manner. 15 min after LTP induction, chelerythrine （200 μmol/L） and G 6983 (100 μmol/L) depressed LTP to baseline in all tested rats. The same concentration of chelerythrine and G 6983, applied at 3 h after LTP induction, did not affect LTP. CONCLUSION: PKC in spinal dorsal horn may be crucial for the induction and the early-phase maintenance of LTP of C-fiber evoked field potentials.