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Decreased A-type potassium current mediates the hyperexcitability of nociceptive neurons in the chronically compressed dorsal root ganglia

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Author:: No author available

Journal Title:: ACTA PHYSIOLOGICA SINICA

Issue:: 2

DOI:: 10.3321/j.issn:0371-0874.2007.02.021

Key Word:: 钾通道;背根神经节;兴奋性;痛

Abstract：慢性压迫大鼠背根神经节(chronic compression of the dorsal root ganglion,CCD)后,背根神经节细胞兴奋性升高,但引起神经元兴奋性改变的离子通道机制还需进一步探索.本实验采用胞内记录以及全细胞膜片钳记录方法,研究急性分离的大鼠背根神经节细胞兴奋性改变与瞬时外向钾电流(A-type potassium current,IA)的关系.结果表明,CCD术后背根神经节细胞兴奋性升高,在急性分离的体外细胞中仍继续存在,表现为对辣椒素敏感的背根神经节细胞产生动作电位的最小电流刺激强度,即阈电流(currentthreshold)及阈电位(voltage threshold)降低;给予正常对照组神经元(未压迫损伤)瞬时外向钾通道阻断剂4-氨基吡啶,出现了类似CCD术后兴奋性升高的改变.进一步用两步电压钳方法分离IA,研究CCD术后神经元IA的变化,结果表明,CCD组神经元的IA比对照组神经元IA降低,并且与其阈电位的改变一致.以上结果提示,背根神经节压迫受损后,神经节细胞IA降低可能参与介导了神经节细胞兴奋性的升高.

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