Molecular and Functional Characterization of Neuronal FMRFamide-Activated Channels

IBN 98-10804价格 组成动物的许多细胞通过化学信号相互交流。 一个细胞释放一种化学物质，另一个细胞通过化学物质与细胞表面的“受体”蛋白质的相互作用来检测这种化学物质。 受体必须将外部信号传递到细胞内部，通常通过在细胞表面打开一个选择性的孔来实现，该孔允许特定的带电离子进出细胞。 选择性孔被称为“离子通道”，受体被称为“门控”通道。 这种信号在神经系统中特别复杂，但离子通道也参与盐和水的平衡，并且在肾脏中特别丰富。 其中一个肾脏通道被称为上皮钠通道，因为它允许钠离子通过。 人们认为上皮钠通道与神经系统中介导化学信号传递的钠通道完全不同，但最近显示神经系统中的一种类型的通道与上皮钠通道相关。 在蜗牛中，一种与神经系统相关的上皮钠通道由一种名为FMRFamide的特殊化学物质门控。FMRFamide是由某些神经细胞释放的肽，因此是一组称为神经肽的信号分子的一个例子。 FMRFamide是已知直接门控离子通道的唯一神经肽，并且其门控的通道是相对已知由神经细胞释放的物质（即，由“神经递质”）门控的唯一上皮钠通道。普赖斯博士从海蛞蝓（一种与陆生蜗牛有亲缘关系的动物，但对神经系统的研究比海蛞蝓广泛得多）中克隆了两种上皮钠通道的部分。 他现在将尝试分离含有这两种通道的全长克隆（含有来自Arachsia的基因的培养细胞），从而可以确定它们的物理性质，并且还可以将它们在神经系统中的定位与已知的FMRFamide的定位进行比较。 这些研究的最终结果将是更好地理解神经肽如何参与动物个体神经细胞的通信，以及这种通信如何介导即使是最简单的动物也表现出的复杂行为。

IBN 98-10804 PRICE Many of the cells that compose an animal communicate with each other by means of chemical signals. One cell releases a chemical which is detected by another cell through the interaction of the chemical with a "receptor" protein on the cell's surface. The receptor must pass the external signal into the interior of the cell and often does so by opening a selective pore in the cell's surface which lets particular charged ions into and out of the cell. The selective pore is called an "ion channel" and the receptor is said to "gate" the channel. Such signaling is especially elaborate in the nervous system, but ion channels are also involved in salt and water balance and are particularly abundant in the kidney. One of the kidney channels is called the epithelial sodium channel because it allows the sodium ion to pass. It was thought that the epithelial sodium channels were completely distinct from sodium channels mediating chemical signal transmission in the nervous system, but it has recently been shown that one type of channel in the nervous system is related to the epithelial sodium channels. In the snail Helix, one such epithelial sodium-channel relative from the nervous system is gated by a particular chemical named FMRFamide. FMRFamide is a peptide released by certain nerve cells and is thus one example of a group of signaling molecules known as neuropeptides. FMRFamide is the only neuropeptide known to directly gate an ion channel and the channel it gates is the only epithelial sodium channel relative known to be gated by a substance released by nerve cells (i.e. by a "neurotransmitter"). Dr. Price has cloned portions of two epithelial sodium channels from the sea slug Aplysia (an animal related to the land-snail, Helix, but with a much more extensively studied nervous system than Helix). He will now try to isolate full length clones (cultured cells containing the gene from Aplysia) containing these two channels so that their physica l properties can be determined and also so that their localization in the nervous system can be compared to the known localization of FMRFamide. The end result of these studies will be a better understanding of how neuropeptides are involved in the communication of individual nerve cells of an animal and how such communication mediates the complex behaviors that even the most simple animals exhibit.