Morphological and biochemical studies on the development of cholinergic properties in cultured sympathetic neurons. II. Dependence on postnatal age.
Morphological and biochemical studies on the development of cholinergic properties in cultured sympathetic neurons. II. Dependence on postnatal age.
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DOI：
10.1083/jcb.84.3.692
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发表时间：
1980-03
期刊：
影响因子：
--
通讯作者：
Bunge RP
中科院分区：
文献类型：
--
作者：
Johnson MI;Ross CD;Bunge RP
取自围产期大鼠并在培养中分离的上级颈神经节（SCG）神经元具有胆碱能特性。本报告探讨了这种“可塑性”的神经递质功能方面的依赖阶段的神经元的发展。将2日龄至成年大鼠的SCG组织块进行培养，观察培养6周后存活神经元的数量。胆碱乙酰转移酶（ChAc）和多巴脱羧酶（DDC）的活性测定每个年龄组随着时间的推移，在文化和突触囊泡人口的细胞化学进行了研究后，去甲肾上腺素负载和KMnO 4固定。在培养的前3- 4天内，所有外植体中ChAc的比活性均下降（继发于突触前末梢的变性），在接下来的30天内，除22天龄和成年大鼠外，所有年龄组的外植体中ChAc的比活性均升高。在培养1个月后发现的最高活性是在2天大的大鼠外植体（62.5 mmol/kg干重/h）;最低的是在成人外植体（1.3 nmol/kg干重/h）。体外培养1个月后，任何年龄动物的外植体之间DDC活性无显著差异（约为220 mmol/kg干重/h）。SCG外植体与心肌的共培养甚至进一步增加了来自2日龄大鼠的外植体中的ChAc活性，但在来自16日龄和6.5周龄动物的外植体中没有增加。1个月龄培养的突触囊泡细胞化学与ChAc活性有很好的相关性，当ChAc活性高时，具有清晰中心的突触囊泡比例为71- 88%。在成年动物的外植体中，只有12%的囊泡含有清晰的中心。从这些数据中，我们得出结论，SCG神经元的成熟度影响它能够调整其神经递质机制的程度。这个神经元的轴突在神经递质可塑性保留期间与靶组织相互作用，这表明与靶组织的相互作用可能在确定递质类型方面发挥作用。
Superior cervical ganglion (SCG) neurons taken from perinatal rats and dissociated in culture develop cholinergic properties. This report examines this "plasticity" of neurotransmitter function with regard to its dependence on the stage of neuronal development. Explants of SCG from rats ranging in age from 2 d to adult were cultured, and the number of neurons surviving after 6 wk in culture was evaluated. The activities of choline acetyltransferase (ChAc) and DOPA decarboxylase (DDC) were assayed for each age group over time in culture, and the cytochemistry of the synaptic vesicle population was studied after norepinephrine loading and KMnO4 fixation. The specific activity of ChAc in all explants fell during the first 3--4 d in culture (secondary to degeneration of presynaptic terminals), with an increase during the next 30 d in explants from all age groups except in those from the 22-d- old and adult rats. The highest activity found after 1 mo in culture was in explants from 2-d-old rats (62.5 mmol per kg dry wt per h); the lowest was in explants from adults (1.3 nmol per kg dry wt per h). After 1 mo in vitro, there were no significant differences in DDC activity among explants from animals of any age (similar to approximately 220 mmol per kg dry wt per h). Co-culture of the SCG explants with heart muscle increased even further the ChAc activity in explants from 2-d-old rats but not in explants from 16-d-old and 6.5-wk- old animals. The cytochemistry of the synaptic vesicle population in 1- mo-old cultures correlated well with the ChAc activity; when the ChAc activity was high, the proportion of synaptic vesicles with clear centers was 71--88%. In explants from adult animals, only 12% of the vesicles contained clear centers. From these data we conclude that the maturity of the SCG neuron influences the degree to which it is able to adjust its neurotransmitter mechanisms. That the axons of this neuron are interacting with target tissues during the time that neurotransmitter plasticity is retained suggests that interaction with the target may play a role in the determination of transmitter type.