Turrigiano G, LeMasson G, Marder E
Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA.
J Neurosci. 1995 May;15(5 Pt 1):3640-52. doi: 10.1523/JNEUROSCI.15-05-03640.1995.
We study the electrical activity patterns and the expression of conductances in adult stomatogastric ganglion (STG) neurons as a function of time in primary cell culture. When first plated in culture, these neurons had few active properties. After 1 d in culture they produced small action potentials that rapidly inactivated during maintained depolarization. After 2 d in culture they fired large action potentials tonically when depolarized, and their properties resembled very closely the properties of STG neurons pharmacologically isolated in the ganglion. After 3-4 d in culture, however, their electrical properties changed and they fired in bursts when depolarized. We characterized the currents expressed by these neurons in culture. They included two TTX-sensitive sodium currents, a calcium current, a delayed-rectifier-like current, a calcium-dependent potassium current, and two A-type currents. The changes in firing properties with time in culture were accompanied by an increase in inward and decrease in outward current densities. A single-compartment conductance-based model of an STG neuron was constructed by fitting the currents measured in the biological neurons. When the current densities in the model neuron were matched to those measured for the biological neurons in each activity state, the model neuron closely reproduced each state, indicating that the changes in current densities are sufficient to account for the changes in intrinsic properties. These data indicate that STG neurons isolated in culture change their intrinsic electrical properties by selectively adjusting the magnitudes of their ionic conductances.
我们研究了成年口胃神经节（STG）神经元的电活动模式和电导表达随原代细胞培养时间的变化。刚接种到培养物中时，这些神经元几乎没有主动特性。培养1天后，它们产生小的动作电位，在持续去极化过程中迅速失活。培养2天后，它们在去极化时持续发放大的动作电位，其特性与在神经节中通过药理学方法分离出的STG神经元的特性非常相似。然而，培养3 - 4天后，它们的电特性发生了变化，去极化时会爆发式发放。我们对这些培养神经元所表达的电流进行了表征。它们包括两种对河豚毒素（TTX）敏感的钠电流、一种钙电流、一种类似延迟整流器的电流、一种钙依赖性钾电流和两种A 型电流。随着培养时间的推移，发放特性的变化伴随着内向电流密度的增加和外向电流密度的降低。通过拟合在生物神经元中测量到的电流，构建了一个基于单室电导的STG神经元模型。当模型神经元中的电流密度与在每种活动状态下生物神经元测量到的电流密度相匹配时，模型神经元能够紧密再现每种状态，这表明电流密度的变化足以解释内在特性的变化。这些数据表明，在培养中分离出的STG神经元通过选择性地调节其离子电导的大小来改变其内在电特性。
