Homberg Uwe, Brandl Christian, Clynen Elke, Schoofs Liliane, Veenstra Jan A
Fachbereich Biologie/Tierphysiologie, Universität Marburg, 35032 Marburg, Germany.
Cell Tissue Res. 2004 Nov;318(2):439-57. doi: 10.1007/s00441-004-0913-7. Epub 2004 Oct 8.
Mas-allatotropin (Mas-AT) and Lom-accessory gland-myotropin I (Lom-AG-MTI) are two members of a conserved family of insect neuropeptides, collectively termed allatotropins, which have diverse functions, ranging from stimulation of juvenile hormone secretion to myotropic effects on heart and hindgut. In addition, allatotropins appear to be abundant within the nervous system, suggesting neuroactive roles. To identify neurons in the insect brain suitable for a neurophysiological analysis of the roles of allatotropins, we used antisera against Mas-AT and Lom-AG-MTI to map allatotropin-immunoreactive neurons in the brain of a suitable insect, the locust Schistocerca gregaria. Both antisera revealed basically identical staining patterns throughout the locust brain with more than 12,500 immunostained interneurons per brain hemisphere. Neurosecretory cells were not labeled, and the retrocerebral complex was devoid of immunostaining. Prominent immunoreactive cell types include about 9,600 lamina monopolar neurons, medulla to lobula interneurons, local neurons of the antennal lobe, a giant interneuron of the mushroom body, projection neurons of the glomerular lobe to the mushroom body, and three systems of tangential neurons of the central complex. Several groups of neurons showed colocalization of Mas-AT- and gamma-aminobutyric acid immunostaining. Mass spectrometric analysis identified a peptide with a molecular mass identical to Lom-AG-MTI in all major parts of the locust brain but not in the retrocerebral complex. This study strongly suggests that Lom-AG-MTI is highly abundant in the locust brain, and is likely to play a neuroactive role in many brain circuits including all stages of sensory processing, learning and memory, and higher levels of motor control.
促咽侧体素（Mas-AT）和飞蝗附腺促肌动蛋白I（Lom-AG-MTI）是昆虫神经肽保守家族的两个成员，统称为促咽侧体素，它们具有多种功能，从刺激保幼激素分泌到对心脏和后肠的促肌效应。此外，促咽侧体素在神经系统中似乎含量丰富，表明其具有神经活性作用。为了鉴定昆虫大脑中适合对促咽侧体素作用进行神经生理学分析的神经元，我们使用针对Mas-AT和Lom-AG-MTI的抗血清，在合适的昆虫——沙漠蝗Schistocerca gregaria的大脑中绘制促咽侧体素免疫反应性神经元图谱。两种抗血清在整个沙漠蝗大脑中显示出基本相同的染色模式，每个脑半球有超过12500个免疫染色的中间神经元。神经分泌细胞未被标记，脑后复合体也没有免疫染色。突出的免疫反应性细胞类型包括约9600个小眼板单极神经元、髓质到小叶中间神经元、触角叶局部神经元、蘑菇体的一个巨型中间神经元、肾小球叶到蘑菇体的投射神经元，以及中央复合体的三个切向神经元系统。几组神经元显示Mas-AT和γ-氨基丁酸免疫染色共定位。质谱分析在沙漠蝗大脑的所有主要部分鉴定出一种分子量与Lom-AG-MTI相同的肽，但在脑后复合体中未鉴定出。这项研究强烈表明，Lom-AG-MTI在沙漠蝗大脑中高度丰富，并且可能在许多脑回路中发挥神经活性作用，包括感觉处理、学习和记忆的所有阶段以及更高水平的运动控制。
