Hermans E, Gailly P, Octave J N, Maloteaux J M
Laboratory of Neurochemistry, Université Catholique de Louvain, Brussels, Belgium.
Biochem Biophys Res Commun. 1994 Jan 14;198(1):400-7. doi: 10.1006/bbrc.1994.1056.
The effect of neurotensin on intracellular calcium mobilization was measured in PC12 cells transfected with the cDNA sequence encoding the rat neurotensin receptor. Stimulation with nanomolar concentrations of neurotensin induced a rapid increase of the [Ca++]i. This response was transient and the [Ca++]i returned to basal level within 2 minutes, despite the continuous presence of the agonist. The response was also observed in the absence of extracellular calcium, indicating the intracellular origin of the released calcium. Successive stimulations with the same concentration of the peptide failed to produce similar responses. ATP was also found to mediate the release from the same intracellular store of calcium in PC12 cells. The amplitude of the response to ATP was not affected by previous stimulation with neurotensin. These results demonstrate the existence of a rapid and homologous desensitization of the neurotensin-induced calcium release in PC12 transfected cells.
在转染了编码大鼠神经降压素受体cDNA序列的PC12细胞中，测定了神经降压素对细胞内钙动员的影响。用纳摩尔浓度的神经降压素刺激可诱导[Ca++]i迅速增加。这种反应是短暂的，尽管激动剂持续存在，[Ca++]i在2分钟内恢复到基础水平。在无细胞外钙的情况下也观察到了这种反应，表明释放的钙来自细胞内。用相同浓度的该肽连续刺激未能产生类似反应。还发现ATP可介导PC12细胞中相同细胞内钙库的钙释放。对ATP反应的幅度不受先前神经降压素刺激的影响。这些结果证明了在转染的PC12细胞中神经降压素诱导的钙释放存在快速同源脱敏现象。
