DEVELOPMENTAL-CHANGES IN THE PROTHORACICOTROPIC HORMONE CONTENT OF THE BOMBYX-MORI BRAIN-RETROCEREBRAL COMPLEX AND HEMOLYMPH - ANALYSIS BY IMMUNOGOLD ELECTRON-MICROSCOPY, QUANTITATIVE IMAGE-ANALYSIS, AND TIME-RESOLVED FLUOROIMMUNOASSAY
DEVELOPMENTAL-CHANGES IN THE PROTHORACICOTROPIC HORMONE CONTENT OF THE BOMBYX-MORI BRAIN-RETROCEREBRAL COMPLEX AND HEMOLYMPH - ANALYSIS BY IMMUNOGOLD ELECTRON-MICROSCOPY, QUANTITATIVE IMAGE-ANALYSIS, AND TIME-RESOLVED FLUOROIMMUNOASSAY
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DOI：
10.1006/dbio.1995.1272
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发表时间：
1995-09-01
影响因子：
2.7
通讯作者：
GILBERT, LI
中科院分区：
文献类型：
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作者：
DAI, JD;MIZOGUCHI, A;GILBERT, LI
昆虫脑神经肽，促胸腺激素(PTTH)，通过刺激前胸腺蜕皮类固醇的生成而引起蜕皮过程。用免疫金电子显微镜和计算机图像分析技术研究了家蚕5龄幼虫和幼蛹变态过程中PTTH亚细胞分布的变化。用时间分辨荧光免疫法测定血淋巴PTTH滴度，用放射免疫法测定血淋巴蜕皮类固醇滴度。免疫反应仅见于脑内两对背外侧神经分泌细胞(La)的胞浆中，即前胸斜纹及其轴突，它们穿过脑神经束的外周区域，然后进入心体的神经血叶，最后到达翼体。5 nm金颗粒对神经分泌颗粒有明显的限制作用，具有明显的免疫特异性。前胸肌的树突侧支与邻近的其他神经元侧支之间存在频繁的突触接触。形态数据表明，PTTH在整个5龄幼虫体内合成和释放。在5龄期间，神经分泌颗粒中金颗粒的浓度和数量增加了5倍，这与血淋巴甲状旁腺素和蜕皮激素效价的升高有关。这些数据表明，PTTH的生物合成、分泌颗粒的形成和分泌是三个连续且几乎同步的事件。(C)1995年学术出版社。
The insect brain neuropeptide, prothoracicotropic hormone (PTTH), elicits the molting process by stimulating ecdysteroido-genesis in the prothoracic glands. Changes in the subcellular distribution of PTTH during the fifth larval instar and larval-pupal metamorphosis of Bombyx were investigated using immunogold electron microscopy and computerized image analysis. A time-resolved fluoroimmunoassay was employed to quantify the hemolymph PTTH titer and the hemolymph ecdysteroid titer was determined by radioimmunoassay. Immunoreactivity was apparent only in the cytoplasm of two pairs of dorsal-lateral neurosecretory cells (La) in the brain, the prothoracicotropes, and their axons that traverse the peripheral area of the brain neuropil and then enter the neurohemal lobes of the corpora cardiaca and end in the corpora allata. Immunospecificity was evident as noted by the restriction of the 5-nm gold particles to the neurosecretory granules. Synaptic contacts were noted frequently between the dendritic collaterals of the prothoracicotropes and neighboring collaterals from other neurons. The morphological data suggest that PTTH is synthesized and released throughout the fifth larval instar. The concentration of gold particles in the neurosecretory granules and the number of neurosecretory granules increased five times during the fifth instar, and these increases were correlated with surges in the hemolymph PTTH and ecdysteroid titers. The data suggest that PTTH biosynthesis, secretory granule formation, and secretion are three continuous and almost synchronized events. (C) 1995 Academic Press, Inc.