Haydon P G, Man-Son-Hing H
Department of Zoology, Iowa State University, Ames 50011.
Neuron. 1988 Dec;1(10):919-27. doi: 10.1016/0896-6273(88)90149-3.
In this study we have characterized two types of Ca2+ currents in identified neuron B5 of Helisoma and have examined the relationship between these currents and neurotransmitter release. Neuron B5 contains low-voltage-activated (LVA) and high-voltage-activated (HVA) Ca2+ currents. These currents have distinct electrophysiological and pharmacological properties. To gain access to the site of neurotransmitter release, we used a model system in which somata that do not extend neurites assume the role of neurotransmitter release. Before somata gain the ability to release neurotransmitter, they contain LVA and HVA Ca2+ currents. After 3 days of culture, when spherical somata have gained the secretory capacity, only the HVA Ca2+ current is present. Experiments were also performed when neurite extension was permitted. These data indicate that neurons with processes have a differential distribution of Ca2+ currents. The soma, which does not release neurotransmitter, contains both LVA and HVA Ca2+ currents, while distal secretory processes contain only HVA current.
在本研究中，我们对椎实螺已鉴定的神经元B5中的两种钙电流进行了特性描述，并研究了这些电流与神经递质释放之间的关系。神经元B5包含低电压激活（LVA）和高电压激活（HVA）钙电流。这些电流具有不同的电生理和药理特性。为了深入了解神经递质释放位点，我们使用了一个模型系统，在该系统中，不延伸神经突的胞体承担神经递质释放的功能。在胞体获得释放神经递质的能力之前，它们含有LVA和HVA钙电流。培养3天后，当球形胞体获得分泌能力时，仅存在HVA钙电流。当允许神经突延伸时也进行了实验。这些数据表明，具有突起的神经元钙电流分布不同。不释放神经递质的胞体同时含有LVA和HVA钙电流，而远端分泌突起仅含有HVA电流。
