Neuropeptide Y in Tiger Puffer (Takifugu rubripes): Distribution, Cloning, Characterization, and mRNA Expression Responses to Prandial Condition
Neuropeptide Y in Tiger Puffer (Takifugu rubripes): Distribution, Cloning, Characterization, and mRNA Expression Responses to Prandial Condition
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DOI：
10.2108/zsj.28.882
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发表时间：
2011-12-01
影响因子：
0.9
通讯作者：
Matsuda, Kouhei
中科院分区：
文献类型：
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作者：
Kamijo, Motoki;Kojima, Kenji;Matsuda, Kouhei
神经肽酪氨酸(NPY)是一种强效的食欲神经肽，与啮齿动物的摄食调节有关。然而，NPY在鱼类摄食行为中的作用还没有得到很好的研究。因此，我们使用虎河豚(Takifugu Rubripe)模型研究了NPY在食物摄入量中的作用。观察NPY样免疫反应在脑内的分布。含NPY的神经元胞体位于端脑、下丘脑、中脑和延髓，其神经纤维也分布于全脑。我们从脑中克隆了两个编码NPYa和NPYb同源基因的cDNA，并在Takifugu基因组数据库中证实了两个编码这些NPY的基因。我们使用实时定量聚合酶链式反应检测了这些转录本在大脑中的分布。端脑、中脑和下丘脑的NPYa基因表达水平明显高于延髓和小脑，延髓的NPYb基因表达水平高于其他区域。我们还检测了膳食对这些转录本在端脑和下丘脑中表达水平的影响。禁食一周的鱼，其下丘脑NPYa基因的表达水平高于正常摄食的鱼，而端脑则未见。在喂养后2小时，其水平有所下降。NPYb基因的表达水平不受膳食条件的影响。这些结果表明，NPY存在于整个大脑中，下丘脑中的NPYa而不是NPYb参与了虎河豚的摄食调节。
Neuropeptide tyrosine (NPY) is a potent orexigenic neuropeptide implicated in feeding regulation in rodents. However, the involvement of NPY in feeding behavior has not well been studied in fish. Therefore, we investigated the role of NPY in food intake using a tiger puffer (Takifugu rubripes) model. We observed the distribution of NPY-like immunoreactivity in the brain. Neuronal cell bodies containing NPY were located in the telencephalon, hypothalamus, mesencephalon, and medulla oblongata, and their nerve fibers were also found throughout the brain. We cloned two cDNAs, encoding NPYa and NPYb orthologs, respectively, from the brain, and also confirmed two genes encoding these NPYs in the Takifugu genome database. We examined the distribution of these transcripts in the brain using real-time PCR. Levels of NPYa mRNA in the telencephalon, mesencephalon and hypothalamus were much higher than in the medulla oblongata and cerebellum, whereas levels of NPYb mRNA in the medulla oblongata were higher than in other regions. We also examined prandial effects on the expression level of these transcripts in the telencephalon and hypothalamus. NPYa mRNA levels in the hypothalamus, but not in the telencephalon, obtained from fish fasted for one week were higher than those in fish that had been fed normally. The level was decreased at 2 h after feeding. Levels of NPYb mRNA were not affected by prandial conditions. These results suggest that NPY is present throughout the brain, and that NPYa, but not NPYb, in the hypothalamus is involved in the feeding regulation in the tiger puffer.