Bruckenstein D, Johnson M I, Higgins D
Department of Pharmacology, School of Medicine, State University of New York, Buffalo 14214.
Brain Res Dev Brain Res. 1989 Mar 1;46(1):21-32. doi: 10.1016/0165-3806(89)90140-5.
We compared the ability of prenatal and postnatal rat sympathetic neurons to form dendrites in tissue culture. Dendrites were distinguished from axons by light microscopic criteria after intracellular dye injection and by differential immunostaining with antibodies to microtubule-associated protein-2 and to both non-phosphorylated and phosphorylated forms of the M and H neurofilament subunits. When maintained in the absence of serum and non-neuronal cells, most (72%) prenatal neurons were unipolar and had only an axon. In contrast, most (89%) neurons derived from postnatal ganglia were multipolar and extended both axons and dendrites. The dendritic morphology of postnatal neurons was usually simple with cells commonly having 2-5 short (50-200 microns), relatively unbranched dendrites. Thus, as the development of the dendritic arbor progresses in situ, sympathetic neurons acquire an enhanced ability to extend dendrites in tissue culture. To determine whether changes in the capacity to develop dendrites might occur with aging in vitro, ganglia were removed from prenatal rats and grown as explants for 3 weeks in the presence of non-neuronal cells; under these conditions, prenatal neurons within the explant became multipolar. When neurons derived from aged explants were subsequently maintained in dissociated cell culture, most formed dendrites. In cultures treated with an antimitotic agent, neurons typically had 1-4 unbranched dendrites; greater amounts of dendritic growth occurred in cultures in which ganglionic non-neuronal cells were allowed to proliferate. We conclude that: (1) the acquisition of the capacity to form dendrites in dissociated cell culture does not require either normal afferent input or physical contact with the target tissue; and (2) even after aging in vitro, sympathetic neurons remain responsive to the dendrite-promoting activity of ganglionic non-neuronal cells.
我们比较了产前和产后大鼠交感神经元在组织培养中形成树突的能力。在进行细胞内染料注射后，通过光学显微镜标准，以及使用针对微管相关蛋白-2、M和H神经丝亚基的非磷酸化和磷酸化形式的抗体进行差异免疫染色，将树突与轴突区分开来。当在无血清和非神经元细胞的条件下培养时，大多数（72%）产前神经元是单极的，只有一条轴突。相比之下，大多数（89%）来自产后神经节的神经元是多极的，既有轴突又有树突。产后神经元的树突形态通常较为简单，细胞通常有2 - 5条短（50 - 200微米）、相对无分支的树突。因此，随着树突分支在原位的发育进展，交感神经元在组织培养中获得了更强的延伸树突的能力。为了确定体外培养时树突发育能力的变化是否会随着衰老而发生，从产前大鼠中取出神经节，并在非神经元细胞存在的情况下作为外植体培养3周；在这些条件下，外植体内的产前神经元变成了多极的。当将来自老化外植体的神经元随后维持在解离细胞培养中时，大多数形成了树突。在用抗有丝分裂剂处理的培养物中，神经元通常有1 - 4条无分支的树突；在允许神经节非神经元细胞增殖的培养物中，树突生长量更大。我们得出以下结论：（1）在解离细胞培养中形成树突的能力的获得既不需要正常的传入输入，也不需要与靶组织的物理接触；（2）即使在体外老化后，交感神经元仍然对神经节非神经元细胞的树突促进活性有反应。
