Fujii J T, Lucaj Z, Peduzzi J D, Crossland W J
Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
J Comp Neurol. 1995 Oct 2;360(4):612-20. doi: 10.1002/cne.903600406.
To determine when the calcium-binding protein parvalbumin appears during development, neurons in the chick Edinger Westphal nucleus were examined for parvalbumin immunoreactivity at a variety of embryonic stages. Parvalbumin immunoreactivity appeared on embryonic day 14 (E14, Hamburger and Hamilton stage 40) in predominantly lateral Edinger Westphal neurons. Cytochrome oxidase activity within the nucleus was examined throughout development, as an indicator of physiological activity, and expression of cytochrome oxidase was compared with that of parvalbumin. Cytochrome oxidase activity was found to be uniformly high in all parts of the Edinger Westphal nucleus throughout development. Either the Edinger Westphal nucleus in physiologically active quite early in its development or other energy demands mask the correlation of cytochrome oxidase with electrical activity. Cytochrome oxidase was expressed well before parvalbumin immunoreactivity appeared. Voltage-activated calcium currents were characterized in E12 Edinger Westphal neurons. In both amplitude and composition, E12 calcium currents resemble those of E16 neurons, excluding the possibility that calcium currents appear de novo during or just prior to the appearance of parvalbumin. Both cytochrome oxidase activity and calcium currents are observed in Edinger Westphal neurons well before the appearance of parvalbumin during development. These findings do not exclude the possibility that physiological activity affects the expression of parvalbumin since other factors such as changing patterns of synaptic activity or the appearance of calcium conducting NMDA receptors have yet to be examined. However, they raise the possibility that additional factors such as an intrinsic developmental program or a change in the neuron's basal intracellular calcium requirements may also be involved.
为了确定钙结合蛋白小白蛋白在发育过程中何时出现，研究人员在多个胚胎阶段检查了鸡胚动眼神经副核中的神经元是否有小白蛋白免疫反应性。小白蛋白免疫反应性在胚胎第14天（E14，汉伯格和汉密尔顿第40阶段）出现在主要位于动眼神经副核外侧的神经元中。在整个发育过程中检测了该核内的细胞色素氧化酶活性，作为生理活动的指标，并将细胞色素氧化酶的表达与小白蛋白的表达进行了比较。发现在整个发育过程中，动眼神经副核的所有部分细胞色素氧化酶活性均一致较高。要么动眼神经副核在其发育早期生理活动就很活跃，要么其他能量需求掩盖了细胞色素氧化酶与电活动的相关性。细胞色素氧化酶在小白蛋白免疫反应性出现之前就已大量表达。对E12动眼神经副核神经元的电压激活钙电流进行了表征。在幅度和组成方面，E12钙电流与E16神经元的钙电流相似，排除了钙电流在小白蛋白出现期间或之前从头出现的可能性。在发育过程中，在小白蛋白出现之前很久，就在动眼神经副核神经元中观察到了细胞色素氧化酶活性和钙电流。这些发现并不排除生理活动影响小白蛋白表达的可能性，因为尚未研究其他因素，如突触活动模式的变化或钙传导性NMDA受体的出现。然而，它们提出了这样一种可能性，即可能还涉及其他因素，如内在的发育程序或神经元基础细胞内钙需求的变化。
