Evolution of Ion Channels

该项目将研究海葵海葵的神经元和海葵的刺细胞(刺细胞)中的离子通道。尽管这种水母中的神经元的功能与所有高等动物中的神经元大致相同，但它们至少有一个属性可能反映了它们的进化地位。它们的钠依赖动作电位的生理学与其他动物的钠电流基本相同，但这些电流的药理是钙电流。由于这些是拥有神经系统的最原始的动物，也是第一个产生钠依赖动作电位的动物，这一发现表明这些神经元可能是钠通道进化的中间产物。这些神经元和刺细胞中的钠和其他离子电流的生理和药理学将用电压钳和单通道记录技术进行检测。此外，有关各种离子通道的结构的信息将通过研究各种离子通道阻滞剂的结合特性而获得。这个项目将提供神经系统如何进化的重要信息。拥有神经系统的最原始动物的离子通道的生理学和药理学将可以与原始和更高级的动物的通道进行比较。通过确定高等动物中离子通道的亚型和等价物，这些结果可能会为一般的神经生物学提供有用的信息。

This project will examine ion channels in neurons of the jellyfish Cyanea capillata and cnidocytes (sting cells) in the sea anemone Anthopleura. Although neurons in this jellyfish function in much the same way as neurons in all higher animals, they have at least one property that may reflect their evolutionary position. The physiology of their sodium-dependent action potentials is essentially the same as that of sodium currents in other animals but the pharmacology of those currents is that of calcium currents. Since these are the most primitive animals to possess a nervous system, and the first to produce sodium-dependent action potentials, this finding suggests that these neurons may be intermediates in sodium channel evolution. The physiology and pharmacology of sodium and other ionic currents in these neurons and in sting cells will be examined with voltage clamp and single channel recording techniques. In addition, information on the structure of the various ion channels will be obtained from studies of the binding characteristics of various ion channel blockers. This project will provide important information about how nervous systems evolved. The physiology and pharmacology of ion channels in the most primitive animals possessing a nervous system will allow comparison with channels in primitive and more advanced animals. The results may provide useful information to neurobiology in general by identifying subtypes of ion channels with equivalents in higher animals.