Pigment-dispersing hormone-immunoreactive neurons and their relation to serotonergic neurons in the blowfly and cockroach visual system
Pigment-dispersing hormone-immunoreactive neurons and their relation to serotonergic neurons in the blowfly and cockroach visual system
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苍蝇和蟑螂视觉系统中色素分散激素免疫反应性神经元及其与血清素能神经元的关系
DOI：
10.1007/bf00318593
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发表时间：
1991
影响因子：
3.6
通讯作者：
K. Ranga Rao
中科院分区：
文献类型：
--
作者：
D. Nässel;S. Shiga;Eva M. Wikstrand;K. Ranga Rao
色素分散激素（PDH）神经肽家族由一系列密切相关的八肽组成，这些八肽从不同的甲壳类动物和昆虫中分离出来，可以在中枢神经系统的神经元和视叶中得到免疫细胞化学证明（Rao和Riehm 1989）。在这项研究中，我们将这些免疫细胞化学研究扩展到包括土生苍蝇和蟑螂。在前一种物种中，组织提取物也在生物测定中进行了测试：苍蝇大脑的提取物表现出类似博士的生物活性，在无柄的招蟹Uca pugilator标本中引起黑色素细胞的分散。使用标准的免疫细胞化学技术，我们可以在苍蝇和蟑螂的视叶神经中发现少量的色素分散激素免疫反应（PDH-IR）神经元。在苍蝇中，这些神经元的细胞体位于髓质的前基部。至少8个PDH-IR细胞体可分为两个大小类别：4个大的和4个小的。分支性免疫反应纤维侵入髓质神经的三层，在突触层的远端和近端各有一层。也可见少量纤维侵入基底小叶和小叶板。远端的纤维似乎来自两个大的PDH-IR细胞体，它们也向髓质输送过程。这些神经元与前面描述的5 -羟色胺免疫反应神经元LBO-5HT在其层状神经形态上有许多共同的特征（见Nässel 1988）。免疫细胞化学双标记可以证明血清素和PDH的免疫反应位于两组不同的神经元中。在蟑螂视叶中发现PDH-IR过程侵入突触层区，并在髓质中形成弥漫性分布。蟑螂的层-髓质细胞的众多细胞体位于层的基底，分成两簇。髓质前基底可见PDH-IR细胞体。结果表明，小强膜中5 -羟色胺免疫反应神经元的分布和形态与PDH-IR神经元非常相似。因此，我们很容易推测，在这两个物种中，pdh和血清素免疫反应神经元在功能上与普通的跟随神经元耦合。这些神经元可能是调节视觉系统中大量单元的候选者。在果蝇中，光感受器的特性可能由突触层周围的两组神经元的作用来调节，可能是由信使的旁分泌释放来调节的。
SummaryThe pigment-dispersing hormone (PDH) family of neuropeptides comprises a series of closely related octadecapeptides, isolated from different species of crustaceans and insects, which can be demonstrated immunocytochemically in neurons in the central nervous system and optic lobes of some representatives of these groups (Rao and Riehm 1989). In this investigation we have extended these immunocytochemical studies to include the blowfly Phormia terraenovae and the cockroach Leucophaea maderae. In the former species tissue extracts were also tested in a bioassay: extracts of blowfly brains exhibited PDH-like biological activity, causing melanophore pigment dispersion in destalked (eyestalkless) specimens of the fiddler crab Uca pugilator. Using standard immunocytochemical techniques, we could demonstrate a small number of pigment-dispersing hormone-immunoreactive (PDH-IR) neurons innervating optic lobe neuropil in the blowfly and the cockroach. In the blowfly the cell bodies of these neurons are located at the anterior base of the medulla. At least eight PDH-IR cell bodies of two size classes can be distinguished: 4 larger and 4 smaller. Branching immunoreactive fibers invade three layers in the medulla neuropil, and one stratum distal and one proximal to the lamina synaptic layer. A few fibers can also be seen invading the basal lobula and the lobula plate. The fibers distal to the lamina appear to be derived from two of the large PDH-IR cell bodies which also send processes into the medulla. These neurons share many features in their laminamedulla morphology with the serotonin immunoreactive neurons LBO-5HT described earlier (see Nässel 1988). It could be demonstrated by immunocytochemical double labeling that the serotonin and PDH immunoreactivities are located in two separate sets of neurons. In the cockroach optic lobe PDH-IR processes were found to invade the lamina synaptic region and form a diffuse distribution in the medulla. The numerous cell bodies of the lamina-medulla cells in the cockroach are located basal to the lamina in two clusters. Additional PDH-IR cell bodies could be found at the anterior base of the medulla. The distribution and morphology of serotonin-immunoreactive neurons in the cockroach lamina was found to be very similar to the PDH-IR ones. It is hence tempting to speculate that in both species the PDH-and serotonin-immunoreactive neurons are functionally coupled with common follower neurons. These neurons may be candidates for regulating large numbers of units in the visual system. In the flies photoreceptor properties may be regulated by action of the two set of neurons at sites peripheral to the lamina synaptic layer, possibly by paracrine release of messengers.