Voltage-gated sodium channels in cerebellar Purkinje cells of mormyrid fish
Voltage-gated sodium channels in cerebellar Purkinje cells of mormyrid fish
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DOI：
10.1152/jn.00906.2005
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发表时间：
2006-07-01
影响因子：
2.5
通讯作者：
Hansel, Christian
中科院分区：
文献类型：
--
作者：
de Ruiter, Martijn M.;De Zeeuw, Chris I.;Hansel, Christian
小脑浦肯野细胞在某些形态和生理参数上与哺乳动物的相应细胞有所不同。在形态上，桑树的浦肯野细胞具有较大的树突，其特点是分子层的分枝程度较低。生理上，与钠通道活动相关的电生理反应模式存在差异：首先，Mormyid Purkinje细胞的钠峰具有低幅度，通常不超过30 mV。其次，神经性浦肯野细胞对攀爬纤维刺激的反应不像哺乳动物那样由复杂的尖峰(带有最初的快钠峰)组成，而是由全有或全无兴奋性突触后电位组成，即所谓的攀升纤维反应。由于这些独特的特性，我们已经开始从电生理学的角度描述桑枝状浦肯野细胞。在这项研究中，我们提供了一个电压门控的Na+通道和电导的浦肯野细胞中的斑点鱼。在啮齿动物的浦肯野细胞中，已经描述了各种类型的Na+通道α亚基，即Na(V)1.1、Na(V)1.2和Na(V)1.6。利用免疫组织化学技术，我们发现这些亚单位存在于Mormyrids的浦肯野细胞中。为了测试这些Na+通道亚基是否能够在Gnathonemus Purkinje细胞中介导快速失活和复苏的Na+电流，我们在急性分离的细胞和小脑切片上进行了膜片钳记录。在大鼠和鱼浦肯野细胞中均可检测到两种类型的Na+电流。这些数据表明，尽管大鼠浦肯野细胞的电生理反应特征显著不同，但它们的电压门控Na+电导是相同的。
Cerebellar Purkinje cells of mormyrid fish differ in some morphological as well as physiological parameters from their counterparts in mammals. Morphologically, Purkinje cells of mormyrids have larger dendrites that are characterized by a lower degree of branching in the molecular layer. Physiologically, there are differences in electrophysiological response patterns that are related to sodium channel activity: first, sodium spikes in mormyrid Purkinje cells have low amplitudes, typically not exceeding 30 mV. Second, the response to climbing fiber stimulation in mormyrid Purkinje cells does not consist of a complex spike (with an initial fast sodium spike) as in mammals, but instead it consists of an all-or-none excitatory postsynaptic potential, the so-called climbing fiber response. Because of these unique properties, we have begun to characterize mormyrid Purkinje cells electrophysiologically. In this study, we provide a description of voltage-gated Na+ channels and conductances in Purkinje cells of the mormyrid fish Gnathonemus petersii. Various types of Na+ channel alpha-subunits, i.e., Na(v)1.1, Na(v)1.2, and Na(v)1.6, have been described in rodent Purkinje cells. Using immunohistochemical techniques, we found that these subunits are present in Purkinje cells of mormyrids. To test whether these Na+ channel subunits can mediate fast inactivating and resurgent Na+ currents in Gnathonemus Purkinje cells, we conducted patch-clamp recordings in acutely dissociated cells and in cerebellar slices. Both types of Na+ currents could be measured in rat and fish Purkinje cells. These data show that, despite prominent differences in electrophysiological response characteristics, Purkinje cells of rats and mormyrids share the same voltage-gated Na+ conductances.