Postnatal development of electrophysiological properties of nucleus accumbens neurons
Postnatal development of electrophysiological properties of nucleus accumbens neurons
复制标题
DOI：
10.1152/jn.2000.84.5.2204
复制
发表时间：
2000-11-01
影响因子：
2.5
通讯作者：
Warren, RA
中科院分区：
文献类型：
--
作者：
Belleau, ML;Warren, RA
应用全细胞膜片钳技术研究了大鼠生后1~49天脑片中脑腹外侧核（nAcb）神经元生理特性的生后发育过程。大多数神经元（102/108）在生理学上被鉴定为中等多刺（MS）投射神经元，只有这些神经元进行了详细的分析。其余的神经元显示出表明它们不是MS神经元的特征。出生前后和出生后第一周，MS神经元的膜和放电特征与后来观察到的有很大不同。这些特征在出生后的前3周内迅速变化，此时它们开始类似于成年人中发现的特征。在研究期间，整个细胞膜电阻和膜时间常数均下降了四倍以上。静息膜电位（RMP）也发生了显著变化，从出生时的平均-50 mV降至出生后第3周末的平均-80 mV以下。在出生后的第一周，所有遇到的MS神经元的电流-电压关系是线性的膜电位以上和以下的RMP在很宽的范围。通过出生后第二周，在超极化范围内显示向内整流的神经元的比例稳步增加，P15后，所有记录的MS神经元显示出显着的向内整流。在所有年龄段，内向整流被细胞外铯和四乙基铵，并没有改变4-氨基吡啶，这表明内向整流介导的年轻和成熟的MS神经元相同的电流。MS神经元早在P1就发出单一和重复的Na +/K+动作电位。尖峰阈值和振幅保持不变，在整个发展过程中，尖峰持续时间，在同一时期显着下降。来自休息的去极化电流脉冲表明，未成熟的MS神经元比它们的老年神经元更容易激发动作电位。两者合计，从本研究的结果表明，年轻和成年nAcb MS神经元整合兴奋性突触输入不同，因为他们的膜和发射特性的差异。这些发现提供了重要的见解nAcb内的信号处理在这个关键时期的发展。
We have studied the postnatal development of the physiological characteristics of nucleus accumbens (nAcb) neurons in slices from postnatal day 1 (P1) to P49 rats using the whole cell patch-clamp technique. The majority of neurons (102/108) were physiologically identified as medium spiny (MS) projection neurons, and only these were subjected to detailed analysis. The remaining neurons displayed characteristics suggesting that they were not MS neurons. Around the time of birth and during the first postnatal weeks, the membrane and firing characteristics of MS neurons were quite different from those observed later. These characteristics changed rapidly during the first 3 postnatal weeks, at which point they began to resemble those found in adults. Both whole cell membrane resistance and membrane time constant decreased more than fourfold during the period studied. The resting membrane potential (RMP) also changed significantly from an average of -50 mV around birth to less than -80 mV by the end of the third postnatal week. During the first postnatal week, the current-voltage relationship of all encountered MS neurons was linear over a wide range of membrane potentials above and below RMP. Through the second postnatal week, the proportion of neurons displaying inward rectification in the hyperpolarized range increased steadily and after P15, all recorded MS neurons displayed significant inward rectification. At all ages, inward rectification was blocked by extracellular cesium and tetra-ethyl ammonium and was not changed by 4-aminopyridine; this shows that inward rectification was mediated by the same currents in young and mature MS neurons. MS neurons fired single and repetitive Na+/K+ action potentials as early as P1. Spike threshold and amplitude remained constant throughout development in contrast to spike duration, which decreased significantly over the same period. Depolarizing current pulses from rest showed that immature MS neurons fired action potentials more easily than their older counterparts. Taken together, the results from the present study suggest that young and adult nAcb MS neurons integrate excitatory synaptic inputs differently because of differences in their membrane and firing properties. These findings provide important insights into signal processing within nAcb during this critical period of development.