Kurylas Angela E, Ott Swidbert R, Schachtner Joachim, Elphick Maurice R, Williams Leslie, Homberg Uwe
Fachbereich Biologie, Tierphysiologie, Philipps-Universität, D-35032 Marburg, Germany.
J Comp Neurol. 2005 Apr 4;484(2):206-23. doi: 10.1002/cne.20467.
Nitric oxide (NO), generated enzymatically by NO synthase (NOS), acts as an important signaling molecule in the nervous systems of vertebrates and invertebrates. In insects, NO has been implicated in development and in various aspects of sensory processing. To understand better the contribution of NO signaling to higher level brain functions, we analyzed the distribution of NOS in the midbrain of a model insect species, the locust Schistocerca gregaria, by using NADPH diaphorase (NADPHd) histochemistry after methanol/formalin fixation; results were validated by NOS immunohistochemistry. NADPHd yielded much higher sensitivity and resolution, but otherwise the two techniques resulted in corresponding labeling patterns throughout the brain, except for intense immunostaining but only weak NADPHd staining in median neurosecretory cells. About 470 neuronal cell bodies in the locust midbrain were NADPHd-positive positive, and nearly all major neuropil centers contained dense, sharply stained arborizations. We report several novel types of NOS-expressing neurons, including small ocellar interneurons and antennal sensory neurons that bypass the antennal lobe. Highly prominent labeling occurred in the central complex, a brain area involved in sky-compass orientation, and was analyzed in detail. Innervation by NOS-expressing fibers was most notable in the central body upper and lower divisions, the lateral accessory lobes, and the noduli. About 170 NADPHd-positive neurons contributed to this innervation, including five classes of tangential neuron, two systems of pontine neuron, and a system of columnar neurons. The results provide new insights into the neurochemical architecture of the central complex and suggest a prominent role for NO signaling in this brain area.
一氧化氮（NO）由一氧化氮合酶（NOS）酶促生成，在脊椎动物和无脊椎动物的神经系统中作为重要的信号分子发挥作用。在昆虫中，NO与发育以及感觉处理的各个方面有关。为了更好地理解NO信号对高级脑功能的贡献，我们通过甲醇/福尔马林固定后使用NADPH黄递酶（NADPHd）组织化学方法，分析了模式昆虫物种沙漠蝗（Schistocerca gregaria）中脑内NOS的分布；结果通过NOS免疫组织化学进行了验证。NADPHd产生了更高的灵敏度和分辨率，但除此之外，这两种技术在整个大脑中产生了相应的标记模式，除了在中位神经分泌细胞中免疫染色强烈但NADPHd染色较弱。沙漠蝗中脑中有约470个神经元细胞体呈NADPHd阳性，几乎所有主要的神经纤维网中心都含有密集、染色清晰的分支。我们报告了几种新型的表达NOS的神经元，包括绕过触角叶的小单眼中间神经元和触角感觉神经元。在中央复合体（一个参与天空罗盘定向的脑区）中出现了高度显著的标记，并进行了详细分析。表达NOS的纤维支配在中央体的上下部、外侧副叶和小结中最为明显。约170个NADPHd阳性神经元参与了这种支配，包括五类切向神经元、两个脑桥神经元系统和一个柱状神经元系统。这些结果为中央复合体的神经化学结构提供了新的见解，并表明NO信号在这个脑区中发挥着重要作用。
