Vita N, Oury-Donat F, Chalon P, Guillemot M, Kaghad M, Bachy A, Thurneyssen O, Garcia S, Poinot-Chazel C, Casellas P, Keane P, Le Fur G, Maffrand J P, Soubrie P, Caput D, Ferrara P
Sanofi Recherche, Labège, France.
Eur J Pharmacol. 1998 Nov 6;360(2-3):265-72. doi: 10.1016/s0014-2999(98)00678-5.
The human levocabastine-sensitive neurotensin NT2 receptor was cloned from a cortex cDNA library and stably expressed in Chinese hamster ovary (CHO) cells in order to study its binding and signalling characteristics. The receptor binds neurotensin as well as several other ligands already described for neurotensin NT1 receptor. It also binds levocabastine, a histamine H1 receptor antagonist that is not recognised by neurotensin NT1 receptor. Neurotensin binding to recombinant neurotensin NT2 receptor expressed in CHO cells does not elicit a biological response as determined by second messenger measurements. Levocabastine, and the peptides neuromedin N and xenin were also ineffective on neurotensin NT2 receptor activation. Experiments with the neurotensin NT1 receptor antagonists SR48692 and SR142948A, resulted in the unanticipated discovery that both molecules are potent agonists on neurotensin NT2 receptor. Both compounds, following binding to neurotensin NT2 receptor, enhance inositol phosphates (IP) formation with a subsequent [Ca2+]i mobilisation; induce arachidonic acid release; and stimulate mitogen-activated protein kinase (MAPK) activity. Interestingly, these activities are antagonised by neurotensin and levocabastine in a concentration-dependent manner. These activities suggest that the human neurotensin NT2 receptor may be of physiological importance and that a natural agonist for the receptor may exist.
从皮质cDNA文库中克隆出人类对左卡巴斯汀敏感的神经降压素NT2受体，并将其稳定表达于中国仓鼠卵巢（CHO）细胞中，以研究其结合和信号转导特性。该受体可结合神经降压素以及已报道的几种神经降压素NT1受体的其他配体。它还能结合左卡巴斯汀，一种组胺H1受体拮抗剂，而神经降压素NT1受体不识别该拮抗剂。通过第二信使测量确定，神经降压素与CHO细胞中表达的重组神经降压素NT2受体结合不会引发生物学反应。左卡巴斯汀、神经调节素N和 Xenin肽对神经降压素NT2受体的激活也无效。使用神经降压素NT1受体拮抗剂SR48692和SR142948A进行的实验意外发现，这两种分子都是神经降压素NT2受体的强效激动剂。这两种化合物与神经降压素NT2受体结合后，均可增强肌醇磷酸（IP）的形成，并随后动员细胞内钙离子浓度（[Ca2+]i）；诱导花生四烯酸释放；并刺激丝裂原活化蛋白激酶（MAPK）活性。有趣的是，这些活性会被神经降压素和左卡巴斯汀以浓度依赖的方式拮抗。这些活性表明人类神经降压素NT2受体可能具有生理重要性，并且可能存在该受体的天然激动剂。
