Precursor forms of substance P (SP) in nervous tissue: detection with antisera to SP, SP-Gly, and SP-Gly-Lys.
Precursor forms of substance P (SP) in nervous tissue: detection with antisera to SP, SP-Gly, and SP-Gly-Lys.
复制标题
神经组织中 P 物质 (SP) 的前体形式：用 SP、SP-Gly 和 SP-Gly-Lys 抗血清进行检测。
DOI：
10.1073/pnas.82.14.4832
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发表时间：
1985
影响因子：
11.1
通讯作者：
Macrides,F
中科院分区：
文献类型：
--
作者：
Kream,RM;Schoenfeld,TA;Mancuso,R;Clancy,AN;el-Bermani,W;Macrides,F
产生的抗血清物质P-Gly（SP-G）和物质P-Gly-Lys（SP-G-K），可能的非酰胺化的COOH-末端延伸形式的P物质，被用来定量和定位物质P前体形式在仓鼠脑干和脊髓。前体决定簇SP-G-K通过组织提取物的温和胰蛋白酶消化从较大的异质形式中释放出来，并通过随后的羧肽酶B处理转化为第二个前体决定簇SP-G。脑干和脊髓中SP-G-K的基础水平约等于0.5 pg/mg组织，胰蛋白酶消化后上升43至64倍。SP-G的基础水平与SP-G-K相当，在联合酶处理后上升了10至29倍。胰蛋白酶消化后，用抗SP-G-K的轴突和胞体的免疫组织化学标记显著增加。该标记通过用真实SP-G-K而不是P物质或SP-G预吸附而消除。凝胶渗透色谱法显示SP-G-K样免疫反应性的馏分对应于相当高的分子量比成熟的P物质。总的来说，这些结果支持这一假设，即P物质是从较大的前体合成，并表明，扩展的前体形式通常存在于轴突和神经系统的胞体，合成P物质。
Antisera generated to substance P-Gly (SP-G) and substance P-Gly-Lys (SP-G-K), the likely unamidated COOH-terminally extended forms of substance P, were used to quantify and localize substance P precursor forms in hamster brain stem and spinal cord. The precursor determinant SP-G-K was liberated from larger heterogeneous forms by mild trypsinization of tissue extracts and was converted into the second precursor determinant, SP-G, by subsequent treatment with carboxypeptidase B. The basal levels of SP-G-K in brain stem and spinal cord were approximately equal to 0.5 pg/mg of tissue and rose 43- to 64-fold after trypsinization. Basal levels of SP-G were comparable to those of SP-G-K and rose 10- to 29-fold after combined enzyme treatments. Immunohistochemical labeling of axons and somata with anti-SP-G-K increased dramatically after trypsinization. This labeling was eliminated by preadsorption with authentic SP-G-K but not substance P or SP-G. Gel-permeation chromatography revealed SP-G-K-like immunoreactivity in fractions corresponding to considerably higher molecular weight than mature substance P. Collectively, these results support the hypothesis that substance P is synthesized from larger precursors and demonstrate that extended precursor forms are normally present in the axons and somata of neural systems that synthesize substance P.