Development of electrophysiological and morphological diversity in autonomic neurons
Development of electrophysiological and morphological diversity in autonomic neurons
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DOI：
10.1152/jn.2001.86.3.1237
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发表时间：
2001-09-01
影响因子：
2.5
通讯作者：
Gibbins, IL
中科院分区：
文献类型：
--
作者：
Anderson, RL;Jobling, P;Gibbins, IL
神经元多样性的产生需要协调发展的差异模式的离子通道的表达沿着与树突状几何形状的特征差异，但这些表型特征之间的关系还不清楚。我们已经使用了细胞内记录，充满染料的神经元的形态学分析，和立体化学标记的部分的特征性的电和形态学分析的组合，以研究从腹腔神经节到内脏血管或豚鼠胃肠道的交感神经元的功能不同的人口的发展特性。在早期胎儿阶段，神经元显着更多的去极化相比，在休息的神经元在后期阶段，他们通常只发射一个动作电位。到胚胎中期，快速和缓慢适应神经元可以区分与地形分布相匹配，发现在成人神经节。大多数快速适应神经元（阶段性神经元）在这个年龄有一个长的后超极化（LAH）的成熟血管神经元的特点，并优先位于神经节的侧极，其中大多数神经元含有神经肽Y。大多数早期和中期胎儿神经元表现出较弱的M电流，这是后来表达的快速适应和LAH神经元。两种不同的A电流存在于早期胎儿神经元的一个子集，并可能表明神经元注定要发展一个缓慢适应表型（紧张神经元）。神经元细胞体的大小在整个发展过程中以类似的速度增加，无论其电气或神经化学表型或其地形位置。相反，神经节内侧区神经元的树突生长速率显著高于外侧区神经元。表观细胞电容与发育神经元的索马表面积高度相关，而与树突树无关。这些结果表明，在腹腔神经节神经元的明确定义的功能群体发展其特征性的电生理和形态学特性在早期胎儿发育阶段。这是在神经元群体可以通过其神经化学和地形特征识别之后，但远在神经元完成生长之前。我们的数据提供了强有力的间接证据，表明自主最终运动神经元的不同功能类别的完整表型的发展是一个多步骤的过程，可能涉及一个调节序列的营养相互作用。
The generation of neuronal diversity requires the coordinated development of differential patterns of ion channel expression along with characteristic differences in dendritic geometry, but the relations between these phenotypic features are not well known. We have used a combination of intracellular recordings, morphological analysis of dye-filled neurons, and stereological analysis of immunohistochemically labeled sections to investigate the development of characteristic electrical and morphological properties of functionally distinct populations of sympathetic neurons that project from the celiac ganglion to the splanchnic vasculature or the gastrointestinal tract of guinea pigs. At early fetal stages, neurons were significantly more depolarized at rest compared with neurons at later stages, and they generally fired only a single action potential. By mid fetal stages, rapidly and slowly adapting neurons could be distinguished with a topographic distribution matching that found in adult ganglia. Most rapidly adapting neurons (phasic neurons) at this age had a long afterhyperpolarization (LAH) characteristic of mature vasomotor neurons and were preferentially located in the lateral poles of the ganglion, where most neurons contained neuropeptide Y. Most early and mid fetal neurons showed a weak M current, which was later expressed only by rapidly-adapting and LAH neurons. Two different A currents were present in a subset of early fetal neurons and may indicate neurons destined to develop a slowly adapting phenotype (tonic neurons). The size of neuronal cell bodies increased at a similar rate throughout development regardless of their electrical or neurochemical phenotype or their topographical location. In contrast, the rate of dendritic growth of neurons in medial regions of the ganglion was significantly higher than that of neurons in lateral regions. The apparent cell capacitance was highly correlated with the surface area of the soma but not the dendritic tree of the developing neurons. These results demonstrate that the well-defined functional populations of neurons in the celiac ganglion develop their characteristic electrophysiological and morphological properties during early fetal stages of development. This is after the neuronal populations can be recognized by their neurochemical and topographical characteristics but long before the neurons have finished growing. Our data provide strong circumstantial evidence that the development of the full phenotype of different functional classes of autonomic final motor neurons is a multi-step process likely to involve a regulated sequence of trophic interactions.