Pfyffer G E, Faivre-Bauman A, Tixier-Vidal A, Norman A W, Heizmann C W
J Neurochem. 1987 Aug;49(2):442-51. doi: 10.1111/j.1471-4159.1987.tb02885.x.
The Ca2+-binding proteins parvalbumin (Mr = 12K) and calbindin D28K [previously designated vitamin D-dependent Ca2+-binding protein (Mr = 28K)] are neuronal markers, but their functional roles in mammalian brain are unknown. The expression of these two proteins was studied by immunocytochemical methods in serum-free cultures of hypothalamic cells from 16-day-old fetal mice. Parvalbumin is first detected in all immature neurons, but during differentiation, the number of parvalbumin-immunoreactive neurons greatly declines to a level reminiscent of that observed in vivo, where only a subpopulation of neurons stains for parvalbumin. In contrast, calbindin D28K was expressed throughout the period investigated only in a distinct subpopulation of neurons. Depolarization of fully differentiated hypothalamic neurons in culture resulted in a dramatic decrease of parvalbumin immunoreactivity but not of calbindin D28K immunoreactivity. The parvalbumin staining was restored on repolarization. Because the anti-parvalbumin serum seems to recognize only the metal-bound form of parvalbumin, the loss of immunoreactivity may signal a release of Ca2+ from intracellular parvalbumin during depolarization of the cells. We suggest that parvalbumin might be involved in Ca2+-dependent processes associated with neurotransmitter release.
钙离子结合蛋白小白蛋白（分子量 = 12K）和钙结合蛋白D28K [以前称为维生素D依赖性钙离子结合蛋白（分子量 = 28K）] 是神经元标志物，但它们在哺乳动物大脑中的功能作用尚不清楚。采用免疫细胞化学方法，对16日龄胎鼠下丘脑细胞的无血清培养物中这两种蛋白的表达进行了研究。在所有未成熟神经元中均可首次检测到小白蛋白，但在分化过程中，小白蛋白免疫反应性神经元的数量大幅下降至类似于在体内观察到的水平，体内只有一部分神经元对小白蛋白染色。相反，钙结合蛋白D28K在所研究的整个时期仅在一个独特的神经元亚群中表达。培养的完全分化的下丘脑神经元去极化导致小白蛋白免疫反应性显著降低，但钙结合蛋白D28K免疫反应性未降低。复极化时小白蛋白染色恢复。由于抗小白蛋白血清似乎仅识别小白蛋白的金属结合形式，免疫反应性的丧失可能表明细胞去极化期间钙离子从小细胞内的白蛋白中释放。我们认为小白蛋白可能参与与神经递质释放相关的钙离子依赖性过程。
