Function of Hormones and Circadian Rhythms in the Regulationof Insect Behavior

激素和昼夜节律在昆虫行为调节中的作用

• 批准号: 8917310
• 负责人: James Truman
• 金额: $ 31.5万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1993-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8917310&HistoricalAwards=false
• 关键词: Function; Hormones; Circadian; Rhythms; Regulationof

A long-term goal of Dr. Truman's program is to understand the role of endocrine factors in the regulation of behavior. This work has focussed on an insect peptide hormone, the eclosion hormone (EH). Studies on moths 20 years ago first indicated the existence of this hormone, and it is now known to be found throughout the insects. Its sole known function is to trigger the behavioral and physiological changes that occur at ecydsis, the time at the end of each molt when the insect sheds to old skin of the former stage. The major target of EH is the central nervous system, which responds to the hormone with a stereotyped program of patterned motor activity which is the basis for the ecdysis behavior. The PI and his colleagues have focussed on two aspects of the ecydsis system: 1) the factors that control the release of EH and 2) the mode of action of this peptide on the nervous system. The system has proven to be very favorable in both regards. The studies in the present proposal are based on a number of advances over the past few years: the determination of the complete structure of EH and production of antibodies against it, the isolation and cloning of the gene that codes for this hormone, and the identification of the neurons that produce and secrete EH. The latter neurons, termed the ventrolateral (VM) cells have a unique position in the brain and send their axons the length of the ventral nervous system to a release site along the hindgut. They appear to be the only neurosecretory cells that project to this area. Their unique position as well as the levels of hormone that they release at each episode (about 90%) make them excellent cells in which to study ultrastructural features of hormone release and of restocking. Also, these cells are very accessible for electrophysiological studies and intracellular and extracellular recording techniques will be used to determine the electrical changes in these cells that result in EH secretion. During the molts of the immature stages, the decline in the levels of steroid hormones at the end of each molt is both necessary and sufficient to cause EH release but then EH, itself, appears to act back to shut-off its own secretion. In the adult, by contrast, these cells respond not only to steroid decline but also to the input from a circadian clock.

杜鲁门博士项目的一个长期目标是了解内分泌因素在行为调控中的作用。这项工作的重点是一种昆虫多肽激素--羽化激素(EH)。20年前对蛾子的研究首次表明这种激素的存在，现在已知在昆虫中也发现了这种激素。它唯一已知的功能是触发蜕皮期发生的行为和生理变化，也就是每次蜕皮结束时昆虫蜕皮到前一阶段的老皮肤。EH的主要目标是中枢神经系统，它通过模式化的运动活动来对激素做出反应，这是蜕皮行为的基础。PI和他的同事们专注于脑溢血系统的两个方面：1)控制EH释放的因素和2)这种多肽对神经系统的作用方式。事实证明，该系统在这两方面都非常有利。本提案中的研究是基于过去几年的一些进展：确定EH的完整结构和产生针对它的抗体，分离和克隆编码这种激素的基因，以及鉴定产生和分泌EH的神经元。后一种神经元，称为腹外(Vm)细胞，在大脑中有一个独特的位置，将它们的轴突发送到腹侧神经系统长度的轴突沿着后肠的释放位置。它们似乎是投射到这一区域的唯一神经分泌细胞。它们独特的位置以及它们在每一集释放的激素水平(约90%)使它们成为研究激素释放和补充库存的超微结构特征的极佳细胞。此外，这些细胞非常容易进行电生理研究，细胞内和细胞外记录技术将被用来确定这些细胞中导致EH分泌的电变化。在未成熟阶段的蜕皮期间，每次蜕皮结束时类固醇激素水平的下降既是必要的，也是导致EH释放的充分条件，但EH本身似乎会反过来关闭自己的分泌。相比之下，在成人中，这些细胞不仅对类固醇下降做出反应，还对生物钟的输入做出反应。