Chabry J, Checler F, Vincent J P, Mazella J
Institut de Pharmacologie Moléculaire et Cellulaire Centre National de la Recherche Scientifique, Valbonne, France.
J Neurosci. 1990 Dec;10(12):3916-21. doi: 10.1523/JNEUROSCI.10-12-03916.1990.
This paper compares the localization of neurotensin receptors and of endopeptidase 24-16, a peptidase likely involved in the inactivation of neurotensin in primary cultures of neurons. Neurotensin binding sites were radiolabeled with 125I-Tyr3-neurotensin, whereas endopeptidase 24-16 was stained by immunohistochemical techniques using a monospecific polyclonal antibody. Endopeptidase 24-16 is present in 80-85% of the nondifferentiated neurons. The proportion of immunoreactive neurons decreased during maturation to reach 35-40% after 4-8 d of culture. By contrast, neurotensin receptors were not detectable in nondifferentiated cells and appear during maturation. Specific 125I-Tyr3-neurotensin labeling is maximal after 4 d of culture and is located on about 10% of differentiated neurons. Double-labeling experiments show that about 90% of cortical, hypothalamic, and mesencephalic neurons bearing the neurotensin receptor also contained endopeptidase 24-16, supporting the hypothesis that one of the functions of endopeptidase 24-16 is the physiological inactivation of neurotensin. However, the presence of endopeptidase 24-16 on numerous neurons that do not contain neurotensin receptors also suggests that the enzyme could be involved in the degradation and/or maturation of other neuropeptides.
本文比较了神经降压素受体和内肽酶24 - 16的定位，内肽酶24 - 16是一种可能参与神经元原代培养中神经降压素失活的肽酶。神经降压素结合位点用125I - Tyr3 - 神经降压素进行放射性标记，而内肽酶24 - 16则使用单特异性多克隆抗体通过免疫组织化学技术进行染色。内肽酶24 - 16存在于80% - 85%的未分化神经元中。在成熟过程中，免疫反应性神经元的比例下降，培养4 - 8天后降至35% - 40%。相比之下，在未分化细胞中未检测到神经降压素受体，其在成熟过程中出现。特异性125I - Tyr3 - 神经降压素标记在培养4天后达到最大值，位于约10%的分化神经元上。双重标记实验表明，约90%的带有神经降压素受体的皮质、下丘脑和中脑神经元也含有内肽酶24 - 16，这支持了内肽酶24 - 16的功能之一是神经降压素的生理性失活这一假设。然而，在众多不含神经降压素受体的神经元上也存在内肽酶24 - 16，这也表明该酶可能参与其他神经肽的降解和/或成熟。
