L-citrulline immunoreactivity reveals nitric oxide production in the electromotor and electrosensory systems of the weakly electric fish, Apteronotus leptorhynchus.
L-citrulline immunoreactivity reveals nitric oxide production in the electromotor and electrosensory systems of the weakly electric fish, Apteronotus leptorhynchus.
复制标题
L-瓜氨酸免疫反应性揭示了弱电鱼 Apteronotus leptorhynchus 的电动机和电感觉系统中一氧化氮的产生。
DOI：
10.1159/000081106
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Gammie,StephenC
中科院分区：
文献类型：
--
作者：
Smith,GTroy;Allen,AntinoR;Oestreich,Jorg;Gammie,StephenC
弱电鱼类产生用于电子定位和通信的电子器官放电(EOD)。在棕色幽灵刀鱼中，控制EOD或处理电感觉信息的大脑区域的几种神经元表达一氧化氮合酶(NOS)。本研究使用一氧化氮合酶产生一氧化氮(NO)的副产物L瓜氨酸的免疫反应来评估一氧化氮合酶表达神经元中一氧化氮的产生。针对L-瓜氨酸的多克隆抗体在大多数以前被发现表达一氧化氮合酶的神经元群体中产生了特异的标记。具体地说，准确编码时间信息和/或高频放电的几种细胞类型，包括电感觉外侧叶的球形细胞，半规管背圆环第VI层的巨细胞，以及起搏核中的起搏和中继细胞，都对L瓜氨酸有较强的免疫反应。这表明这些神经元产生了高水平的NO。值得注意的是，同样强烈表达一氧化氮合酶的电动运动神经元没有L瓜氨酸的免疫反应，这表明一氧化氮合酶在这些神经元中不会产生高水平的NO。在被社会隔离的鱼和暴露于模拟同种生物存在的回放刺激的鱼之间，没有观察到明显的L瓜氨酸分布或强度的差异。这表明，在许多一氧化氮合酶阳性神经元中，通过电通讯信号进行社会刺激并不是产生高水平NO所必需的。未来的研究将集中在这些系统中NO产生的调控，以及NO在电感觉加工和电动模式产生中的作用，这将有助于阐明NO信号通路在该系统中的功能。
Weakly electric fish produce electric organ discharges (EODs) used for electrolocation and communication. In the brown ghost knifefish, Apteronotus leptorhynchus, several neuron types in brain regions that control the EOD or process electrosensory information express nitric oxide synthase (NOS). The present study used immunoreactivity for L-citrulline, a byproduct of the production of nitric oxide (NO) by NOS, to assess NO production in NOS-expressing neurons. A polyclonal antibody against L-citrulline produced specific labeling in most neuronal populations previously identified to express NOS. Specifically, several cell types that precisely encode temporal information and/or fire at high frequencies, including spherical cells in the electrosensory lateral line lobe, giant cells in layer VI of the dorsal torus semicircularis, and pacemaker and relay cells in the pacemaker nucleus, were strongly immunoreactive for L-citrulline. This suggests that these neurons produced high levels of NO. Notably, electromotor neurons, which also strongly express NOS, were not immunoreactive for L-citrulline, suggesting that NOS did not produce high levels of NO in these neurons. No apparent differences in L-citrulline distribution or intensity were observed between socially isolated fish and fish exposed to playback stimuli simulating the presence of a conspecific. This suggests that social stimulation by electrocommunication signals is not necessary for high levels of NO production in many NOS-positive neurons. Future studies focusing on regulation of NO production in these systems, and the effects of NO on electrosensory processing and electromotor pattern generation will help elucidate the function of NO signaling pathways in this system.