Siegl Theresa, Schachtner Joachim, Holstein Gay R, Homberg Uwe
Philipps Universität Marburg, Germany.
Cell Tissue Res. 2009 Aug;337(2):327-40. doi: 10.1007/s00441-009-0820-z. Epub 2009 Jun 9.
Nitric oxide (NO) is a gaseous messenger molecule formed during conversion of L: -arginine into L: -citrulline by the enzyme NO synthase (NOS), which belongs to a group of NADPH diaphorases. Because of its gaseous diffusion properties, NO differs from classical neurotransmitters in that it is not restricted to synaptic terminals. In target cells, NO activates soluble guanylyl cyclase leading to an increase in cGMP levels. In insects, this NO/cGMP-signalling pathway is involved in development, memory formation and processing of visual, olfactory and mechanosensory information. We have analysed the distribution of putative NO donor and target cells in the central complex, a brain area involved in sky-compass orientation, of the locust Schistocerca gregaria by immunostaining for L: -citrulline and cGMP. Six types of citrulline-immunostained neurons have been identified including a bilateral pair of hitherto undescribed neurons that connect the lateral accessory lobes with areas anterior to the medial lobes of the mushroom bodies. Three-dimensional reconstructions have revealed the connectivity pattern of a set of 18 immunostained pontine neurons of the central body. All these neurons appear to be a subset of previously mapped NADPH-diaphorase-positive neurons of the central complex. At least three types of central-complex neurons show cGMP immunostaining including a system of novel columnar neurons connecting the upper division of the central body and the lateral triangle of the lateral accessory lobe. Our results provide the morphological basis for further studies of the function of the labelled neurons and new insights into NO/cGMP signalling.
一氧化氮（NO）是一种气态信使分子，由一氧化氮合酶（NOS）将L-精氨酸转化为L-瓜氨酸的过程中形成，一氧化氮合酶属于NADPH黄递酶家族。由于其气态扩散特性，NO与经典神经递质不同，它不限于突触终末。在靶细胞中，NO激活可溶性鸟苷酸环化酶，导致cGMP水平升高。在昆虫中，这种NO/cGMP信号通路参与发育、记忆形成以及视觉、嗅觉和机械感觉信息的处理。我们通过对L-瓜氨酸和cGMP进行免疫染色，分析了沙漠蝗Schistocerca gregaria中参与天空罗盘定向的脑区中央复合体中假定的NO供体细胞和靶细胞的分布。已鉴定出六种瓜氨酸免疫染色神经元，包括一对迄今为止未描述的双侧神经元，它们将外侧副叶与蘑菇体中叶前方的区域相连。三维重建揭示了一组18个中央体免疫染色脑桥神经元的连接模式。所有这些神经元似乎都是中央复合体中先前绘制的NADPH黄递酶阳性神经元的一个子集。至少三种类型的中央复合体神经元显示cGMP免疫染色，包括一个连接中央体上部和外侧副叶外侧三角的新型柱状神经元系统。我们的结果为进一步研究标记神经元的功能提供了形态学基础，并为NO/cGMP信号传导提供了新的见解。
