NEURITE BRANCH DEVELOPMENT OF AN IDENTIFIED SEROTONERGIC NEURON FROM EMBRYONIC HELISOMA - EVIDENCE FOR AUTOREGULATION BY SEROTONIN
NEURITE BRANCH DEVELOPMENT OF AN IDENTIFIED SEROTONERGIC NEURON FROM EMBRYONIC HELISOMA - EVIDENCE FOR AUTOREGULATION BY SEROTONIN
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DOI：
10.1006/dbio.1995.1023
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发表时间：
1995-01-01
影响因子：
2.7
通讯作者：
GOLDBERG, JI
中科院分区：
文献类型：
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作者：
DIEFENBACH, TJ;SLOLEY, BD;GOLDBERG, JI
先前的研究表明，在选定的神经元中，神经突的生长可以受到这些神经元合成和释放的相同神经递质的调节。然而，尚不清楚在无脊椎动物或脊椎动物神经系统发育的正常过程中是否利用了这种自动调节机制。在本研究中，我们在肺腹足动物 Helisoma trivolvis 胚胎中表达的第一对已鉴定的血清素能神经元上测试了这一假设。胚胎神经元 C1 (ENC1) 在随后的血清素能神经元分化之前详细阐述了神经突生长的刻板模式。用对氯苯丙氨酸 (pCPA) 或 5-羟色氨酸 (5-HTP) 处理胚胎，分别降低或提高胚胎血清素含量。使用电化学检测的高效液相色谱来测量这些处理对血清素含量的影响，并进行血清素免疫组织化学来量化 ENC1 神经突生长的程度。用 0.02% pCPA 处理后 24 小时和 48 小时，胚胎血清素含量显着降低，而多巴胺水平没有变化。尽管 ENC1 的近端神经突生长在这两个时间点似乎均未受到 pCPA 处理的影响，但靶细胞区域的远端生长似乎更为丰富。这种对生长的影响通过计算神经突分支点的数量来量化，在 pCPA 处理后 24 小时和 48 小时，神经突分支点的数量均显着增加。相比之下，5-HTP 处理导致胚胎血清素含量增加，ENC1 分支点数量显着减少。多巴胺治疗对 ENC1 神经突生长模式没有影响。总之，这些结果支持这样的假设：神经元可能以自动调节方式利用其自身的递质来调节胚胎发育过程中的神经突形成。 (C) 1995 学术出版社
Previous studies have shown that in select neurons, neurite outgrowth can be regulated by the same neurotransmitter that is synthesized and released by those neurons. However, it is not known whether such an autoregulatory mechanism is utilized during the normal course of nervous system development in either invertebrates or vertebrates. In the present study, we tested this hypothesis on the first pair of identified serotonergic neurons to be expressed in embryos of the pulmonate gastropod, Helisoma trivolvis. Embryonic neurons C1 (ENC1) elaborate a stereotyped pattern of neurite outgrowth prior to the differentiation of subsequent serotonergic neurons. Embryos were treated with either p-chlorophenylalanine (pCPA) or 5-hydroxytryptophan (5-HTP) to lower or raise embryonic serotonin content, respectively. High-performance liquid chromatography with electrochemical detection was used to measure the effects of these treatments on serotonin content, and serotonin immunohistochemistry was carried out to quantify the extent of neurite outgrowth of ENC1. Embryonic serotonin content was significantly reduced at both 24 and 48 hr after treatment with 0.02% pCPA, whereas dopamine levels were unchanged. Although the proximal neurite outgrowth of ENC1 appeared unaffected by the pCPA treatment at both of these time points, the distal outgrowth in the target cell region appeared more profuse. This effect on outgrowth was quantified by counting the number of neurite branch points, which was significantly increased both 24 and 48 hr after pCPA treatment. In contrast, 5-HTP treatment resulted in an increase in embryonic serotonin content and a significant decrease in the number of ENC1 branch points. Treatment with dopamine had no effect on the pattern of ENC1 neurite outgrowth. Together, these results support the hypothesis that a neuron may utilize its own transmitter in an autoregulatory fashion to regulate neurite formation during embryonic development. (C) 1995 Academic Press, Inc.