Mikkelsen J D, Larsen P J, Møller M, Vilhardt H, Saermark T
Institute of Medical Anatomy, University of Copenhagen, Denmark.
Neuroendocrinology. 1989 Jul;50(1):100-8. doi: 10.1159/000125208.
The distribution of substance P was demonstrated by immunohistochemical methods, and receptor binding with 125I-8-iodinated 8-tyrosine-substance P as an analog was used to describe possible specific binding sites in the hypothalamo-hypophysial system of the rat. The immunohistochemical experiments showed fibers exhibiting substance P-immunoreactivity in the external and internal layer of the median eminence. In the external layer some of the fibers were located in apposition to the portal capillaries. In the posterior pituitary substance P-immunoreactive fibers were identified. These terminals varied in size and were located near the capillaries as well as in the neuropil. The anterior lobe contained a number of substance P-immunoreactive fibers distributed around the pituitary cells. The kinetic analysis on crude membrane fractions from anterior and posterior pituitaries revealed the presence of a specific binding site for substance P in the anterior pituitary. These data indicate that substance P may be released from the median eminence and posterior pituitary to the vascular system and reach specific receptors in the anterior pituitary. However, a direct innervation of the anterior pituitary is possible. The lack of binding sites in the posterior pituitary indicates that fibers in this organ release substance P into the blood stream.
采用免疫组织化学方法证实了P物质的分布，并使用125I-8-碘化8-酪氨酸-P物质作为类似物的受体结合来描述大鼠下丘脑-垂体系统中可能的特异性结合位点。免疫组织化学实验显示，在正中隆起的外层和内层有呈现P物质免疫反应性的纤维。在外层，一些纤维位于门静脉毛细血管附近。在后叶垂体中鉴定出了P物质免疫反应性纤维。这些终末大小各异，位于毛细血管附近以及神经毡中。前叶含有许多围绕垂体细胞分布的P物质免疫反应性纤维。对来自前叶和后叶垂体的粗膜部分进行的动力学分析显示，前叶垂体中存在P物质的特异性结合位点。这些数据表明，P物质可能从中部隆起和后叶垂体释放到血管系统中，并到达前叶垂体中的特异性受体。然而，前叶垂体存在直接神经支配也是有可能的。后叶垂体中缺乏结合位点表明该器官中的纤维将P物质释放到血流中。
