Discovery of leucokinin-like neuropeptides that modulate a specific parameter of feeding motor programs in the molluscan model, Aplysia
Discovery of leucokinin-like neuropeptides that modulate a specific parameter of feeding motor programs in the molluscan model, Aplysia
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发现白细胞激肽样神经肽，可调节软体动物模型海兔中摄食运动程序的特定参数
DOI：
10.1074/jbc.m117.795450
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发表时间：
2017-11-17
影响因子：
4.8
通讯作者：
Jing, Jian
中科院分区：
文献类型：
--
作者：
Zhang, Guo;Vilim, Ferdinand S.;Jing, Jian
为了更好地理解行为系统中的神经调节，需要识别主动调节递质。在这里，我们使用神经生物学模型系统中可识别的神经元，软体动物应用，来研究神经肽，一种不同类型的神经调节剂。我们利用了海兔颊神经节中可能含有不同神经肽的两种喂养神经元B48和B1/B2。我们通过减去B48中的mrna与B1/B2中的mrna进行了代表性差异分析（RDA）。RDA鉴定了一个异常长的（2025个氨基酸）肽前体，编码白斑白蛋白样肽（alk，如ALK-1和ALK-2）。Northern blot分析显示，与其他神经节（如踏板-胸膜神经节）相比，ALK mRNA主要存在于控制摄食行为的颊神经节。然后，我们使用原位杂交和免疫组织化学将alk定位到特定的神经元，包括B48。MALDI-TOF质谱在单个颊神经元上显示40个ALK前体衍生肽的表达。其中，ALK-1和ALK-2在摄食网络中活跃；他们缩短了由类似命令的神经元触发的进食运动程序的radula延长阶段。我们还发现，这种效应可能是由alk刺激的中间神经元活动增强介导的，而中间神经元的活动增强先前已被证明可以终止延长。我们得出的结论是，我们的多管齐下的方法是有效的确定结构和定义不同功能的白蛋白样肽。值得注意的是，ALK前体是第一个被证实的非节肢动物的白蛋白样肽前体，它对摄食运动程序的特定参数（延长时间）具有新的、显著的调节作用。
A better understanding of neuromodulation in a behavioral system requires identification of active modulatory transmitters. Here, we used identifiable neurons in a neurobiological model system, the mollusc Aplysia, to study neuropeptides, a diverse class of neuromodulators. We took advantage of two types of feeding neurons, B48 and B1/B2, in the Aplysia buccal ganglion that might contain different neuropeptides. We performed a representational difference analysis (RDA) by subtraction of mRNAs in B48 versus mRNAs in B1/B2. The RDA identified an unusually long (2025 amino acids) peptide precursor encoding Aplysia leucokinin-like peptides (ALKs; e.g. ALK-1 and ALK-2). Northern blot analysis revealed that, compared with other ganglia (e.g. the pedal-pleural ganglion), ALK mRNA is predominantly present in the buccal ganglion, which controls feeding behavior. We then used in situ hybridization and immunohistochemistry to localize ALKs to specific neurons, including B48. MALDI-TOF MS on single buccal neurons revealed expression of 40 ALK precursor-derived peptides. Among these, ALK-1 and ALK-2 are active in the feeding network; they shortened the radula protraction phase of feeding motor programs triggered by a command-like neuron. We also found that this effect may be mediated by the ALK-stimulated enhancement of activity of an interneuron, which has previously been shown to terminate protraction. We conclude that our multipronged approach is effective for determining the structure and defining the diverse functions of leucokinin-like peptides. Notably, the ALK precursor is the first verified nonarthropod precursor for leucokinin-like peptides with a novel, marked modulatory effect on a specific parameter (protraction duration) of feeding motor programs.