3 TYPES OF SODIUM-CHANNELS IN ADULT-RAT DORSAL-ROOT GANGLION NEURONS
3 TYPES OF SODIUM-CHANNELS IN ADULT-RAT DORSAL-ROOT GANGLION NEURONS
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DOI：
10.1016/0006-8993(92)91687-a
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发表时间：
1992-10-02
期刊：
影响因子：
2.9
通讯作者：
KOCSIS, JD
中科院分区：
文献类型：
--
作者：
CAFFREY, JM;ENG, DL;KOCSIS, JD
几种类型的Na+电流先前已被证明在背根神经节（DRG）神经元分离的新生大鼠，但其在成年神经元的表达还没有研究。应用微电极电流钳、膜片钳和免疫细胞化学技术，在原代培养的成年大鼠背根神经节（DRG）神经元上研究了不同大小的DRG神经元Na+电流特性。细胞内电流钳记录确定了不同的相对贡献TTX敏感性和抗内向电流动作电位波形在DRG神经元群体的定义大小。膜片钳记录确定了三种不同的动力学类型的Na+电流差异分布在这些大小类的DRG神经元。“小”DRG神经元共表达两种类型的Na+电流：（i）快速失活的、TTX敏感的“快”电流和（ii）缓慢激活和失活的、TTX抗性的“慢”电流。在典型的静息电位下，这些细胞中的TTX敏感性Na+电流几乎完全失活。“大”细胞表达一个单一的TTX敏感的Na+电流确定为“中间”的失活速率常数。“中等”大小的神经元要么共同表达“快”和“慢”电流，要么只表达“中间”电流。Na+通道表达在这些大小的类，也测定了免疫细胞化学技术。针对脑型Na+通道的抗体（Ab7493）10以相似的强度标记小神经元和大神经元。这些结果表明，可以检测到三种类型的Na+电流与成人大鼠DRG神经元的生理和解剖学上不同的群体的产电特性。
Several types of Na+ currents have previously been demonstrated in dorsal root ganglion (DRG) neurons isolated from neonatal rats, but their expression in adult neurons has not been studied. Na+ current properties in adult dorsal root ganglion (DRG) neurons of defined size class were investigated in isolated neurons maintained in primary culture using a combination of microelectrode current clamp, patch voltage clamp and immunocytochemical techniques. Intracellular current clamp recordings identified differing relative contributions of TTX-sensitive and -resistant inward currents to action potential waveforms in DRG neuronal populations of defined size. Patch voltage clamp recordings identified three distinct kinetic types of Na+ current differentially distributed among these size classes of DRG neurons. 'Small' DRG neurons co-express two types of Na+ current: (i) a rapidly-inactivating, TTX-sensitive 'fast' current and (ii) a slowly-activating and -inactivating, TTX-resistant 'slow' current. The TTX-sensitive Na+ current in these cells was almost completely inactivated at typical resting potentials. 'Large' cells expressed a single TTX-sensitive Na+ current identified as 'intermediate' by its inactivation rate constants. 'Medium'-sized neurons either co-expressed 'fast' and 'slow' current or expressed only 'intermediate' current. Na+ channel expression in these size classes was also measured by immunocytochemical techniques. An antibody against brain-type Na+ channels (Ab7493)10 labeled small and large neurons with similar intensity. These results demonstrate that three types of Na+ currents can be detected which correlate with electrogenic properties of physiologically and anatomically distinct populations of adult rat DRG neurons.