大鼠背根神经节神经元上失活BK通道特性的研究

Inactivating Calcium-activated Potassium Currents in Rat Dorsal Root Ganglia Neurons

大电导的电压和Ca2+激活的K+通道(BK通道)在哺乳动物的组织中广泛表达,起着多种多样的作用.目前只有少数组织中BK通道的性质被深入地研究,而且鲜见有失活的BK通道(BKi)的报道,尤其是在神经元中.发现在大鼠小直径的背根神经节(DRG)神经元中,普遍存在失活的BK通道.失活的BK电流成分是Ca2+敏感的,可以被大电导的BK通道特异阻断剂ChTX所阻断,而且木瓜蛋白酶可以从胞外改变通道失活的特性.

Large conductance voltage and Ca2+-activated K+ channels (BK channels), which are ubiquitously expressed among mammalian tissues, play a variety of physiological roles. The inactivating BK channels have not been extensively studied in primary tissues and rarely do they exhibit inactivation. An inactivating BK current (BKi) was identified in rat small dorsal root ganglia (DRG) neurons. The inactivating currents are sensitive to the specific BK channel blocker charybdotoxin (ChTX) and the effect of ChTX can be removed partially when washed with normal external solution. The inactivation of BKi can be removed by external treatment of papain.