Sodium current of neurosecretory cells in the eyestalk from the shrimp Penaeus japonicus  

作　　者：Jinshen Liu Shiying Li Haihui Ye Guizhong Wang 

机构地区：[1]Department of Oceanography, Xiamen University, Xiamen 361005, China [2]Xiamen Institute of Medicine, Xiamen 361003, China [3]State Key Laboratory of Marine Environment Science, Xiamen 361005, China

出　　处：《Progress in Natural Science:Materials International》2009年第11期1493-1499,共7页自然科学进展·国际材料（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.30300269);the Technical Innovation Project of Fujian(Grant No. 2003J018)

摘　　要：The properties of the inward current of medulla terminalis-X-organ （MTXO） cells isolated from the Penaeusjaponicus eyestalk were studied with the whole-cell clamp technique in the presence of Ca^2＋ and K^＋ channel blockers. The inward currents had a threshold at about -50 mV and peaked at -10 mV. The reversed potential （Vrev） was very close to VNa, the theoretical Nernst equilibrium potential for Na^＋. Vrev followed VNa when the external Na^＋ concentration was varied and the currents were entirely suppressed by 30 nM tetrodotoxin （TTX）, indicating that it was carried by Na^＋. The smooth line of concentration-dependent inhibition of sodium currents by TTX represented the best fit with the Hill equation, yielding an IC50 of 2.1 ± 0.1 nM. The values of the half-maximal activation voltage Vh were -20.6 ± 0.5 and -19.3 ± 0.5 mV, respectively, in the absence and presence of 2 nM TTX. TTX had no significant effect on the voltage dependence of steady-state activation and inactivation of INa. Taken together, the results suggest that the inward current recorded under our experimental conditions was carried by sodium ions flowing through fast voltage-dependent Na^＋ channels.房间从 Penaeus 孤立的髓质 terminalis-X-organ (MTXO ) 的里面的水流的性质日本我们眼柄被学习与整个房间面对 Ca ²⁺ 和 K ⁺ 隧道块夹钳技术 ers。里面的水流有阀值在大约 &#x2212； 50 mV 并且在 &#x2212 达到顶点； 10 mV。颠倒的潜力(V <sub > 加快 </sub>) 离 V <sub 很靠近 > Na </sub>, 为 Na ⁺ 的理论 Nernst 平衡潜力。V <sub > 加快 </sub> 跟随了 V <sub > Na </sub> 当外部 Na ⁺ 集中被改变，水流被 30 nM tetrodotoxin (TTX ) 完全压制时，显示它被 Na ⁺ 带。由 TTX 的钠水流的集中依赖者抑制的光滑的线代表了与山方程合适的最好，产出 2.1 &#xb1 的 IC ₅₀ ； 0.1 nM。一半最大的激活电压 V <sub 的价值 > h </sub> 是 &#x2212； 20.6 &#xb1； 0.5 并且 &#x2212； 19.3 &#xb1； 0.5 mV，分别地在 2 nM TTX 的缺席和存在。TTX 没在不变的激活并且在激活的电压依赖上有重要效果我 <sub > Na </sub> 。总起来说，结果建议在我们的试验性的条件下面记录的里面的电流被通过快电压依赖者 Na ⁺ 隧道流动的钠离子带。

关 键 词：MTXO Sodium current Penaeusjaponicus PATCH-CLAMP 

分 类 号：Q959.223.5[生物学—动物学] Q959.226