Harzsch Steffen, Dircksen Heinrich, Beltz Barbara S
Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Strasse 8, 07745 Jena, Germany.
Cell Tissue Res. 2009 Feb;335(2):417-29. doi: 10.1007/s00441-008-0728-z. Epub 2008 Nov 26.
We have examined the development of pigment-dispersing hormone (PDH)-immunoreactive neurons in embryos of the American lobster Homarus americanus Milne Edwards, 1837 (Decapoda, Reptantia, Homarida) by using an antiserum against beta-PDH. This peptide is detectable in the terminal medulla of the eyestalks and the protocerebrum where PDH immunoreactivity is present as early as 20% of embryonic development. During ontogenesis, an elaborate system of PDH-immunoreactive neurons and fibres develops in the eyestalks and the protocerebrum, whereas less labelling is present in the deuto- and tritocerebrum and the ventral nerve cord. The sinus gland is innervated by PDH neurites at hatching. This pattern of PDH immunoreactivity has been compared with that found in various insect species. Neurons immunoreactive to pigment-dispersing factor in the medulla have been shown to be a central component of the system that generates the circadian rhythm in insects. Our results indicate that, in view of the position of the neuronal somata and projection patterns of their neurites, the immunolabelled medulla neurons in insects have homologous counterparts in the crustacean eyestalk. Since locomotory and other activities in crustaceans follow distinct circadian rhythms comparable with those observed in insects, we suggest that PDH-immunoreactive medulla neurons in crustaceans are involved in the generation of these rhythms.
我们利用抗β-色素分散激素（PDH）的抗血清，研究了1837年米尔恩·爱德华兹命名的美洲龙虾（十足目，爬行亚目，龙虾科）胚胎中PDH免疫反应性神经元的发育情况。早在胚胎发育的20%阶段，就能在眼柄的终髓和原脑检测到这种肽，而此处存在PDH免疫反应性。在个体发育过程中，眼柄和原脑中形成了一个复杂的PDH免疫反应性神经元和纤维系统，而在中脑和后脑以及腹神经索中的标记较少。孵化时，窦腺由PDH神经突支配。已将这种PDH免疫反应性模式与在各种昆虫物种中发现的模式进行了比较。已证明，髓质中对色素分散因子有免疫反应的神经元是昆虫中产生昼夜节律系统的核心组成部分。我们的结果表明，鉴于神经元胞体的位置及其神经突的投射模式，昆虫中经免疫标记的髓质神经元在甲壳类动物眼柄中有同源对应物。由于甲壳类动物的运动和其他活动遵循与昆虫中观察到的明显昼夜节律相当的节律，我们认为甲壳类动物中PDH免疫反应性髓质神经元参与了这些节律的产生。
