Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany.
Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, Würzburg, Germany.
J Comp Neurol. 2021 Jun;529(8):1876-1894. doi: 10.1002/cne.25062. Epub 2020 Nov 9.
The central complex is a group of highly interconnected neuropils in the insect brain. It is involved in the control of spatial orientation, based on external compass cues and various internal needs. The functional and neurochemical organization of the central complex has been studied in detail in the desert locust Schistocerca gregaria. In addition to classical neurotransmitters, immunocytochemistry has provided evidence for a major contribution of neuropeptides to neural signaling within the central complex. To complement these data, we have identified all orcokinin-immunoreactive neurons in the locust central complex and associated brain areas. About 50 bilateral pairs of neurons innervating all substructures of the central complex exhibit orcokinin immunoreactivity. Among these were about 20 columnar neurons, 33 bilateral pairs of tangential neurons of the central body, and seven pairs of tangential neurons of the protocerebral bridge. In silico transcript analysis suggests the presence of eight different orcokinin-A type peptides in the desert locust. Double label experiments showed that all orcokinin-immunostained tangential neurons of the lateral accessory lobe cluster were also immunoreactive for GABA and the GABA-synthesizing enzyme glutamic acid decarboxylase. Two types of tangential neurons of the upper division of the central body were, furthermore, also labeled with an antiserum against Dip-allatostatin I. No colocalization was found with serotonin immunostaining. The data provide additional insights into the neurochemical organization of the locust central complex and suggest that orcokinin-peptides of the orcokinin-A gene act as neuroactive substances at all stages of signal processing in this brain area.
中央复合神经系统是昆虫脑中高度互联的神经节团，它参与基于外部罗盘线索和各种内部需求的空间定向控制。沙漠蝗 Schistocerca gregaria 中央复合神经系统的功能和神经化学组织已被详细研究。除了经典神经递质外，免疫细胞化学还为神经肽在中央复合神经系统内的神经信号传递中做出重大贡献提供了证据。为了补充这些数据，我们鉴定了蝗虫中央复合神经系统及其相关脑区中所有的 orcokinin-免疫反应性神经元。约 50 对双侧成对神经元支配中央复合体的所有亚结构，表现出 orcokinin 免疫反应性。其中约有 20 个柱状神经元、33 对中央体的双侧切线神经元和 7 对protocerebral bridge 的切线神经元。计算机转录分析表明，沙漠蝗中存在八种不同的 orcokinin-A 型肽。双标记实验表明， lateral accessory lobe cluster 的所有 orcokinin-免疫染色的切线神经元也对 GABA 和 GABA 合成酶谷氨酸脱羧酶呈免疫反应性。此外，中央体上部分的两种类型的切线神经元也被 Dip-allatostatin I 的抗血清标记。与血清素免疫染色没有共定位。这些数据提供了关于蝗虫中央复合神经系统神经化学组织的更多见解，并表明在该脑区的信号处理的所有阶段，orcokinin-A 基因的 orcokinin 肽作为神经活性物质发挥作用。
