Cable properties of spinal cord motoneurons in adult and aged cats.
Cable properties of spinal cord motoneurons in adult and aged cats.
复制标题
成年猫和老年猫脊髓运动神经元的电缆特性。
DOI：
10.1152/jn.1989.61.1.194
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发表时间：
1989
影响因子：
2.5
通讯作者：
Chase,MH
中科院分区：
文献类型：
--
作者：
Engelhardt,JK;Morales,FR;Yamuy,J;Chase,MH
1.应用细胞内记录技术研究了成年猫（1-3岁）和老年猫（14-15岁）脊髓α运动神经元的电生理特性。根据Ito和Oshima（15）描述的程序分析去极化电流脉冲后的电压瞬变。每个细胞的输入电阻，连同被动电时间常数，被用来估计每个运动神经元的电紧张长度和总细胞电容。2.在阈下去极化电流脉冲停止后，成年和老年运动神经元均表现出膜电位的下冲（15）。在成年和老年动物的运动神经元中，膜电位下冲衰减的平均时间常数在统计学上无法区分。3.老年猫运动神经元的平均膜时间常数比成年猫运动神经元的平均膜时间常数长19%。4.老年猫运动神经元的平均总细胞电容比成年猫运动神经元的平均总细胞电容小16%。5.老年运动神经元的平均电紧张长度与成年猫的运动神经元的平均电紧张长度在统计学上没有区别。6.从这些结果中，我们得出结论，有一个年龄依赖性的膜电阻增加和年龄依赖性的细胞表面积减少的α-运动神经元在老年猫的腰髓。这两种现象都被认为有助于输入阻力的年龄依赖性增加，这在以前的报道中已经发生在老年猫的运动神经元中（18）。
1. The electrophysiological properties of spinal cord alpha-motoneurons were investigated in adult cats (1-3 yr old) and old cats (14-15 yr old) using intracellular recording techniques. Voltage transients following depolarizing pulses of current were analyzed according to the procedure described by Ito and Oshima (15). The input resistance of each cell, together with the passive electrical time constants, were used to estimate the electrotonic length and total cell capacitance of each motoneuron. 2. Adult and old motoneurons both exhibited an undershoot of the membrane potential following the cessation of a subthreshold depolarizing current pulse (15). The average time constant for the decay of this undershoot in membrane potential was statistically indistinguishable in motoneurons of adult and aged animals. 3. The average membrane time constant of motoneurons in aged cats was 19% longer than that of motoneurons in adult cats. 4. The average total cell capacitance of motoneurons in aged cats was 16% smaller than that of motoneurons in adult cats. 5. The average electrotonic length of old motoneurons was statistically indistinguishable from that of motoneurons in adult cats. 6. From these results, we conclude that there is an age-dependent increase in the membrane resistance and an age-dependent decrease in cell surface area of alpha-motoneurons of the lumbar spinal cord in aged cats. Both of these phenomena are believed to contribute to the age-dependent increase in input resistance that has been previously reported to occur in motoneurons in aged cats (18).