Meurling P, Rodríguez E M, Peña P, Grondona J M, Pérez J
Department of Zoology, University of Lund, Sweden.
J Comp Neurol. 1996 Sep 23;373(3):400-21. doi: 10.1002/(SICI)1096-9861(19960923)373:3<400::AID-CNE6>3.0.CO;2-6.
Immunocytochemistry using antibodies against the neurohypophysial nonapeptides has given equivocal results regarding relevant aspects of the classical neurosecretory system of elasmobranchs. The lack of antibodies reacting with the elasmobranch neurophysins (Nps) has prevented the study of this neurosecretory system by Nps immunocytochemistry. This led us to purify Nps from Scyliorhinus canicula, and to use them to raise a polyclonal antibody. This antibody reacted strongly with the elasmobranch neurophysin neurons, revealing their most delicate and distant hypophysial and extrahypophysial projections. A detailed mapping of the neurosecretory system of five elasmobranch species (Etmopterus spinax, Squalus acanthias, Scyliorhinus canicula, Galeus melanostomus, Raja radiata) and one holocephalian species (Hydrolagus colliei) was performed. In elasmobranchs, the magnocellular neurophysin cells formed a distinct preoptic nucleus, whereas in Hydrolagus the immunoreactive cells were scattered. Distinct parvicellular neurophysin cells were present in the preoptic nucleus. In Raja the nucleus "O" contained parvicellular Nps-immunoreactive neurons. The findings at the pituitary level point to the possibility that neurophysin neurons, in addition to releasing nonapeptides into the systemic capillaries of the neural lobe, also participate in the regulation of the function of the rostral, medial and intermediate lobes of the adenohypophysis by a dual mechanism, i.e., a neurovascular pathway and a direct neural input. The extrahypophysial projections of the neurophysin neurons were highly developed to a degree not comparable to any other vertebrate group. The targets of these projections were located in the telencephalon, diencephalon and hindbrain. The evolutionary and functional implications of this phenomenon are discussed.
使用针对神经垂体九肽的抗体进行免疫细胞化学研究，在有关板鳃亚纲动物经典神经分泌系统的相关方面得出了不明确的结果。缺乏与板鳃亚纲动物神经垂体素（Nps）发生反应的抗体，阻碍了通过Nps免疫细胞化学对该神经分泌系统的研究。这促使我们从犬鲨中纯化Nps，并使用它们来制备多克隆抗体。该抗体与板鳃亚纲动物的神经垂体素神经元发生强烈反应，揭示了它们最细微和最远端的垂体及垂体外投射。对五种板鳃亚纲动物（刺鲨、棘鲨、犬鲨、黑口 Galeus melanostomus、放射鳐 Raja radiata）和一种全头亚纲动物（科氏银鲛 Hydrolagus colliei）的神经分泌系统进行了详细绘图。在板鳃亚纲动物中，大细胞神经垂体素细胞形成一个明显的视前核，而在科氏银鲛中，免疫反应性细胞则是分散的。视前核中存在明显的小细胞神经垂体素细胞。在放射鳐中，“O”核含有小细胞Nps免疫反应性神经元。垂体水平的研究结果表明，神经垂体素神经元除了将九肽释放到神经叶的体循环毛细血管中外，还可能通过神经血管途径和直接神经输入这一双重机制，参与腺垂体的 Rostral、内侧和中间叶功能的调节。神经垂体素神经元的垂体外投射高度发达，其程度与其他任何脊椎动物类群都不可比。这些投射的靶标位于端脑、间脑和后脑。讨论了这一现象的进化和功能意义。
