Fedulova S A, Kostyuk P G, Veselovsky N S
Bogomoletz Institute of Physiology, Ukrainian Academy of Sciences, Kiev, U.S.S.R.
Neuroscience. 1991;41(1):303-9. doi: 10.1016/0306-4522(91)90219-e.
Inward currents in the somatic membrane of rat dorsal root ganglion neurons have been studied in three groups of animals (8-10, 45-50 and 90-100 days of postnatal development) by intracellular perfusion and voltage clamp techniques. Altogether, 228 neurons have been examined (76 in each age group). Four components have been identified in the inward current: fast tetrodotoxin-sensitive (IfNa) and slow tetrodotoxin-insensitive (IsNa) sodium, low threshold (IlCa) and high threshold (IhCa) calcium currents. The existence of certain types of inward currents in the somatic membrane allowed the heterogeneous population of all the investigated neurons to be divided into six homogeneous subpopulations. A significant decrease in the percentage of neurons was found, demonstrating four types of inward currents (IfNa, IsNa, IlCa, IhCa) during postnatal ontogenesis. The percentage of cells in the subpopulation showing only IfNa and IhCa increased from 26% in the first age group to 43% in the second and 62% in the third age groups. Correlations between densities of various types of inward currents were studied. A linear relationship was found between the densities of IhCa and IsNa in subpopulations of neurons with IsNa. An inverse dependence was observed between the densities of IfNa and IhCa in cells showing only two current components. In all cells studied a "washout" of IhCa was observed during intracellular dialysis with saline solutions. Recovery of calcium conductance produced by intracellular application of an cAMP-ATP-Mg2+ complex was different in neurons with various inward current combinations. Intracellular introduction of cAMP-ATP-Mg2+ failed to restore IhCa in most cells of the second and third age groups.(ABSTRACT TRUNCATED AT 250 WORDS)
通过细胞内灌注和电压钳技术，对三组动物（出生后发育8 - 10天、45 - 50天和90 - 100天）的大鼠背根神经节神经元的体膜内向电流进行了研究。总共检查了228个神经元（每个年龄组76个）。在内向电流中鉴定出四个成分：快速河豚毒素敏感（IfNa）和慢速河豚毒素不敏感（IsNa）钠电流、低阈值（IlCa）和高阈值（IhCa）钙电流。体膜中某些类型内向电流的存在，使得所有被研究神经元的异质群体被分为六个同质亚群。发现在出生后的个体发育过程中，显示四种内向电流（IfNa、IsNa、IlCa、IhCa）的神经元百分比显著下降。仅显示IfNa和IhCa的亚群中的细胞百分比从第一年龄组的26%增加到第二年龄组的43%和第三年龄组的62%。研究了各种类型内向电流密度之间的相关性。在具有IsNa的神经元亚群中，发现IhCa和IsNa的密度之间存在线性关系。在仅显示两种电流成分的细胞中，观察到IfNa和IhCa的密度之间呈反比关系。在所有研究的细胞中，在用盐溶液进行细胞内透析期间，观察到IhCa的“洗脱”。在具有不同内向电流组合的神经元中，通过细胞内应用cAMP - ATP - Mg2 +复合物产生的钙电导恢复情况不同。在第二和第三年龄组的大多数细胞中，细胞内引入cAMP - ATP - Mg2 +未能恢复IhCa。（摘要截断于250字）
