Protein synthesis inhibition blocks the late-phase LTP of C-fiber evoked field potentials in rat spinal dorsal horn
Protein synthesis inhibition blocks the late-phase LTP of C-fiber evoked field potentials in rat spinal dorsal horn
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DOI：
10.1152/jn.01027.2002
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发表时间：
2003-05-01
影响因子：
2.5
通讯作者：
Liu, XG
中科院分区：
文献类型：
--
作者：
Hu, NW;Zhang, HM;Liu, XG
以往的研究表明，在海马的长时程增强（LTP）的维持需要从头蛋白质合成。为探讨蛋白质合成在脊髓背角C纤维诱发场电位LTP维持中的作用，并探讨其可能与痛觉过敏的关系，将蛋白质合成抑制剂（放线菌酮或茴香霉素）在强直刺激坐骨神经前30 min局部应用于麻醉大鼠脊髓记录段。我们发现，放线菌酮和茴香霉素选择性地抑制脊髓LTP的后期维持，但既不影响LTP的诱导，也不影响C-纤维诱发场电位的基线反应。在放线菌酮存在下，强直刺激后1h C-纤维诱发场电位的LTP为基线的281.5 ± 16.5%（n = 6），强直刺激后145 min增强显著降低至235.5 ± 18.5%（P < 0.05）。强直刺激后C纤维诱发场电位LTP持续下降，270 min达130.8 ± 18.0%，与刺激前无显著性差异（P > 0.05）。在强直刺激前30分钟脊髓应用茴香霉素产生了类似的结果（n = 6）。这些结果表明，蛋白质的合成可能是至关重要的后期维持C-纤维诱发场电位在脊髓背角的LTP。
Previous studies have demonstrated that in the hippocampus the maintenance of long-term potentiation (LTP) requires de novo protein synthesis. To investigate the role of protein synthesis in the maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn, which may be relevant to hyperalgesia, protein synthesis inhibitor ( either cycloheximide or anisomycin) was applied locally to the recording segments of spinal cord in anesthetized rats, 30 min prior to tetanic stimulation to the sciatic nerve. We found that both cycloheximide and anisomycin selectively inhibited late-phase maintenance of the spinal LTP but affected neither LTP induction nor baseline responses of C-fiber evoked field potentials. In the presence of cycloheximide, LTP of C-fiber evoked field potentials was 281.5 +/- 16.5% (n = 6) of baseline 1 h after tetanic stimulation and the potentiation significantly decreased to 235.5 +/- 18.5% at 145 min after tetanic stimulation (P < 0.05). Afterward, LTP of C-fiber evoked field potentials decreased continuously and at 270 min after tetanic stimulation reached 130.8 ± 18.0%, which was no longer different from baseline (P > 0.05). Spinal application of anisomycin at 30 min before tetanic stimulation yielded similar results (n = 6). These results suggest that protein synthesis may be crucial for the late-phase maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn.