Berman N J, Hincke M T, Maler L
Department of Anatomy and Neurobiology, Faculty of Medicine, University of Ottawa, Ontario, Canada.
J Comp Neurol. 1995 Oct 23;361(3):512-24. doi: 10.1002/cne.903610313.
Inositol 1,4,5-trisphosphate is a widespread intracellular second messenger that mobilizes intracellular Ca2+ stores. The inositol 1,4,5-trisphosphate receptor involved is associated with the endoplasmic reticulum in neurons. In mammalian brain, inositol 1,4,5-trisphosphate receptor-containing neurons are found in many diverse regions, with cerebellar Purkinje cells containing the highest density of these receptors. We used immunohistochemical methods to identify the distribution of inositol 1,4,5-trisphosphate receptor-containing neurons in the brain of the weakly electric fish and Western blotting to confirm that a protein similar to the inositol 1,4,5-trisphosphate receptor of mammalian brain was recognized in the fish brain. In the telencephelon, the dorsal forebrain regions had low amounts of inositol 1,4,5-trisphosphate receptor. In the diencephalon, only the nucleus tuberis posterior was moderately immunoreactive. In the mesencephalon, only the optic tectum contained cells with intense immunoreactivity, similar to our findings for the ryanodine receptor (G.K.H. Zupanc, J.A. Airey, L. Maler, J. Sutko, and M.H. Ellisman, 1992, J. Comp. Neurol. 325:135-151), which also mobilizes intracellular calcium. In the rhombencephalon, a subset of the pyramidal cells of the electrosensory lateral line lobe contained inositol 1,4,5-trisphosphate receptor. These cells have been shown to contain ryanodine receptor (Zupanc et al., 1992). However, unlike the ryanodine receptor, the distribution of inositol 1,4,5-trisphosphate receptor in these cells is constrained to the soma and proximal dendrites. This compartmentalization may indicate the limit of the range of second-messenger action. Other regions containing immunoreactive cells were the nucleus praeminentialis dorsalis (multipolar and boundary cells), nucleus medialis and crista cerebellaris, and the cerebellum, whose Purkinje cells were the most intensely labeled. The functional implications of inositol 1,4,5-trisphosphate receptor localization in the electrosensory lateral line lobe are discussed.
肌醇1,4,5 -三磷酸是一种广泛存在的细胞内第二信使，可动员细胞内的钙库。所涉及的肌醇1,4,5 -三磷酸受体与神经元内质网相关。在哺乳动物大脑中，含有肌醇1,4,5 -三磷酸受体的神经元存在于许多不同区域，其中小脑浦肯野细胞中这些受体的密度最高。我们使用免疫组织化学方法来确定弱电鱼大脑中含有肌醇1,4,5 -三磷酸受体的神经元的分布，并通过蛋白质印迹法来确认在鱼脑中识别出了一种与哺乳动物大脑肌醇1,4,5 -三磷酸受体相似的蛋白质。在端脑，背侧前脑区域的肌醇1,4,5 -三磷酸受体含量较低。在间脑，只有结节后核有中等程度的免疫反应性。在中脑，只有视顶盖含有免疫反应强烈的细胞，这与我们对兰尼碱受体的研究结果相似（G.K.H.祖潘克、J.A.艾里、L.马勒、J.苏特科和M.H.埃利斯曼，1992年，《比较神经学杂志》325:135 - 151），兰尼碱受体也能动员细胞内钙。在菱脑，电感觉侧线叶的一部分锥体细胞含有肌醇1,4,5 -三磷酸受体。这些细胞已被证明含有兰尼碱受体（祖潘克等人，1992年）。然而，与兰尼碱受体不同的是，这些细胞中肌醇1,4,5 -三磷酸受体的分布局限于胞体和近端树突。这种区域化可能表明第二信使作用范围的限制。其他含有免疫反应性细胞的区域是背侧前主核（多极细胞和边界细胞）、内侧核和小脑嵴，以及小脑，其浦肯野细胞的标记最为强烈。文中讨论了肌醇1,4,5 -三磷酸受体在电感觉侧线叶中的定位的功能意义。
