Fahrbach S E, Truman J W
Department of Zoology, University of Washington, Seattle 98195.
J Neurobiol. 1989 Dec;20(8):681-702. doi: 10.1002/neu.480200803.
The steroid hormone 20-hydroxyecdysone regulates many aspects of nervous system development in the moth Manduca sexta, including stage-specific neuronal morphology and stage-specific neuronal death. We have used steroid hormone autoradiography to study the distribution of cells that concentrate ecdysteroids in the ventral nervous system of this insect. The ligand was [3H]-ponasterone A, a bioactive phytoecdysone. Tissue was examined from three stages of development: the end of larval life (first day of wandering), the end of metamorphosis (pharate adult), and 4-day-old adults. In the abdominal ganglia of wandering larvae and pharate adults, a subset of neurons including both motoneurons and interneurons exhibited a nuclear concentration of radiolabeled hormone. The pattern of binding was reproducible but stage-specific, with a greater proportion of neurons showing binding in the larvae than in pharate adults. No labeled neurons were found in abdominal ganglia from mature (4-day-old) adults. In the case of the pharate adult ganglia, the ecdysteroid receptor content of specific, identified motoneurons was determined. These results are discussed in light of the responses of these neurons to physiological changes in levels of circulating ecdysteroids.
类固醇激素20-羟基蜕皮酮调节烟草天蛾神经系统发育的多个方面，包括特定阶段的神经元形态和特定阶段的神经元死亡。我们利用类固醇激素放射自显影技术研究了该昆虫腹侧神经系统中浓缩蜕皮甾体的细胞分布。配体是[3H]-蜕皮甾酮A，一种具有生物活性的植物蜕皮激素。研究了三个发育阶段的组织：幼虫生命末期（化蛹前一天）、变态末期（预蛹）和4日龄成虫。在化蛹前幼虫和预蛹的腹神经节中，包括运动神经元和中间神经元在内的一部分神经元显示出放射性标记激素的核浓缩。结合模式是可重复的，但具有阶段特异性，与预蛹相比，幼虫中显示结合的神经元比例更高。在成熟（4日龄）成虫的腹神经节中未发现标记神经元。对于预蛹神经节，测定了特定的、已识别的运动神经元的蜕皮甾体受体含量。根据这些神经元对循环蜕皮甾体水平生理变化的反应对这些结果进行了讨论。
