作　　者： ; ; ; ; ; ; ;

机构地区： 中国人民解放军第一军医大学

出　　处： 《生物化学与生物物理进展》 2003年第6期874-878,共5页

摘　　要： 采用膜片钳内面向外式技术 ,在急性分离成年大鼠海马CAl区锥体细胞上记录到了外向整流氯离子通道(outwardlyrectifyingchloridechannel ,ORCC) .长时间去极化 (≥ 60mV)刺激后 ,在 3 0 %的游离膜片上记录到有外向整流特性的单通道氯电流 ,膜电位在 -60mV到 0mV之间的单通道电导为 (16 58± 1 54) pS (n =10 ) ,而在 0mV到 + 60mV之间电导为 (40 92± 3 17)pS .通道开放概率有明显的电压依赖性 (膜电位 -60mV时 ,Po=0 44± 0 12 ;膜电位为 + 60mV时 ,Po=0 86± 0 0 6,n =10 ) .在对称Cl- 浓度 (150mmol/L)时 ,通道翻转电位为 (-4 17± 1 84)mV .当溶液中部分NaCl被葡萄糖酸钠替代后 ,翻转电位为 :(-3 4 2 3± 4 86)mV ([Cl- ] i/ [Cl- ] o=(3 0mmol/L) / (150mmol/L) ) ,接近氯离子通道的理论值 ,这表明通道具有氯离子选择性 .浴槽液中分别加入氯通道阻断剂DIDS和SITS可以使 + 4 0mV的通道开放概率从 (0 83± 0 0 6)和(0 86± 0 0 6)分别降低到 (0 12± 0 0 5)和 (0 13± 0 0 4) (n =5) ,冲洗后可使开放概率基本恢复 .上述研究结果显示 。 An outwardly rectifying chloride channel (ORCC) was ch aracterized in acutely dissociated hippocampal CA1 pyramidal neurons of adult rat by using inside-out configuration of patch clamp. The channels were usually activated by a long-lasting and depolarizing voltage step. Average single channel conductance was (16 58± 1 54) pS for membrane potential between -60 mV an d 0 mV, and (40 92±3 17) pS between 0 mV and +60 mV in symmetrical 150 mmol/L Na Cl solution (n=10). The channel open probability was voltage dependent (V m= -60 m V ,P o=0 44±0 12;V m=+60 mV,P o=0 86±0 06, n=10). The reversal potential of the channel was (-4 17±1 84) mV in symmetrical Cl - concentration (150 mmol/L). When partially substituting Na-Gluconate for Na Cl, the reversal potential shifted to (-34 23±4 86) mV ( i/ o=( 30 mmol/L )/(150 mmol/L)). This shift indicates a high Cl - selectiv ity of the channel. Chloride channel blockers DIDS and SITS showed a reversible inhibiting effect on the channel activity. These results provide a report of an outwardly rectifying chloride channel (ORCC) in hippocampal CA1 pyramidal neurons of adult rat.

关 键 词： 氯离子通道 膜片钳 海马 大鼠 锥体神经元

领　　域： [生物学] [生物学]