Kameyama M
J Membr Biol. 1983;72(3):195-203. doi: 10.1007/BF01870586.
Ionic currents in cultured dorsal root ganglion (DRG) neurons from adult guinea pigs were analyzed by voltage-clamp techniques. The Na+ inward current had a reversal potential at +33 mV, and revealed activation and inactivation kinetics similar to those of squid giant axons. A typical value for the maximum Na+ conductance was 178 mS/cm2 and the peak current was 2.5 mA/cm2. The delayed K+ outward current showed a fast and a slow phase of inactivation and was sensitive to tetraethylammonium (TEA; approximately 130 mM) and 4-aminopyridine (approximately 2 mM). The maximum K+ conductance was 26 +/- 9 (mean +/- SD) mS/cm2. The slow Ca2+ inward current was identified in Na+-free, TEA-containing solution. Its peak value was increased by 1.7-fold when [Ca2+]o was increased from 5 to 10 mM. The current was blocked by Co2+ but not by tetrodotoxin. Sr2+ and Ba2+ could substitute in carrying this current. The maximum peak of the Ca2+ current was 0.22 +/- 0.14 mA/cm2. At potentials positive to 0 mV, the Ca2+ current was often followed by a slowly developing outward current, which was also sensitive to Co2+, suggesting a Ca2+-activated outward current. It is concluded that the action potential of the adult guinea pig DRG neuron is mediated by Ca2+ as well as by Na+ and K+ currents. The current densities of these ionic channels are considered to be different from embryonic neurons and from nodes of Ranvier.
采用电压钳技术分析了成年豚鼠培养的背根神经节（DRG）神经元中的离子电流。Na⁺内向电流的反转电位为+33 mV，其激活和失活动力学与乌贼巨轴突相似。最大Na⁺电导的典型值为178 mS/cm²，峰值电流为2.5 mA/cm²。延迟的K⁺外向电流表现出快速和缓慢的失活阶段，并且对四乙铵（TEA；约130 mM）和4-氨基吡啶（约2 mM）敏感。最大K⁺电导为26±9（平均值±标准差）mS/cm²。在无Na⁺、含TEA的溶液中鉴定出缓慢的Ca²⁺内向电流。当[Ca²⁺]ₒ从5 mM增加到10 mM时，其峰值增加了1.7倍。该电流被Co²⁺阻断，但不被河豚毒素阻断。Sr²⁺和Ba²⁺可以替代携带该电流。Ca²⁺电流的最大峰值为0.22±0.14 mA/cm²。在高于0 mV的电位下，Ca²⁺电流之后通常会跟随一个缓慢发展的外向电流，该电流也对Co²⁺敏感，表明存在Ca²⁺激活的外向电流。结论是成年豚鼠DRG神经元的动作电位由Ca²⁺以及Na⁺和K⁺电流介导。这些离子通道的电流密度被认为与胚胎神经元和郎飞结不同。
