Brouard A, Pelaprat D, Dana C, Vial M, Lhiaubet A M, Rostène W
Institut National de la Santé et de la Recherche Médicale, Unité 339, Hôpital Saint Antoine, Paris, France.
J Neurosci. 1992 Apr;12(4):1409-15. doi: 10.1523/JNEUROSCI.12-04-01409.1992.
The cellular distribution and functional aspects of neurotensin (NT) binding sites in rat mesencephalic cells in primary culture were investigated by an original approach combining anatomical and biochemical studies. Using a double-labeling protocol combining 125I-NT receptor radioautography and tyrosine hydroxylase (TH) immunocytochemistry, we obtained the first direct visualization of NT binding sites on TH-immunoreactive neurons. Eighty percent of the TH neurons were endowed with NT binding sites, which can be observed on both cell bodies and processes. TH-immunoreactive neurons were characterized as dopaminergic neurons by their ability to take up dopamine in a benztropine- and nomifensine-sensitive manner. In the mesencephalic cultures, NT increased potassium-evoked release of tritiated dopamine, and the relative potencies of various NT-related peptides to increase dopamine release were in good agreement with their abilities to bind to NT sites. These results show for the first time that cultured rat mesencephalic dopaminergic cells express functional NT receptors. Finally, the specificity and distribution of NT receptors on dopaminergic neurons in primary culture are quite similar to what was observed in the adult rat brain using pharmacological and radioautographic approaches. These data indicate that NT can influence the activity of dopaminergic neurons at very early stages of the rat brain development.
采用解剖学和生物化学研究相结合的原创方法，对原代培养的大鼠中脑细胞中神经降压素（NT）结合位点的细胞分布和功能方面进行了研究。通过结合125I-NT受体放射自显影和酪氨酸羟化酶（TH）免疫细胞化学的双标记方案，我们首次直接观察到TH免疫反应性神经元上的NT结合位点。80%的TH神经元具有NT结合位点，在细胞体和突起上均可观察到。TH免疫反应性神经元通过其以苯海索和诺米芬辛敏感的方式摄取多巴胺的能力被表征为多巴胺能神经元。在中脑培养物中，NT增加了钾诱导的氚化多巴胺释放，各种NT相关肽增加多巴胺释放的相对效力与其结合NT位点的能力高度一致。这些结果首次表明，培养的大鼠中脑多巴胺能细胞表达功能性NT受体。最后，原代培养的多巴胺能神经元上NT受体的特异性和分布与在成年大鼠脑中使用药理学和放射自显影方法观察到的情况非常相似。这些数据表明，NT在大鼠脑发育的非常早期阶段就能影响多巴胺能神经元的活性。
