Mason Sarah, Smart Darren, Marshall Ian C B, McKnight Alexander, Skepper Jeremy N, McNulty Shaun
Pfizer Global Research and Development, Cambridge Laboratories, Cambridge University Forvie Site, Robinson Way, Cambridge CB2 2QB, UK.
Eur J Pharmacol. 2002 Mar 1;438(1-2):25-34. doi: 10.1016/s0014-2999(02)01268-2.
Reverse transcription polymerase chain reaction (RT-PCR) demonstrated the presence of bombesin BB2 receptor mRNA but not bombesin BB1 receptor or bombesin BB3 receptor mRNA in cultured human astrocytes. Neuromedin C hyperpolarised human astrocytes in whole-cell current and voltage clamp recordings and increased the intracellular free Ca(2+) ion concentration (Ca(2+)) in single astrocytes. Treatment with neuromedin C caused larger and more frequent increases in Ca(2+) than those triggered by neuromedin B, with 96% and 78% of cells responding, respectively. The stimulatory effects of neuromedin C were inhibited significantly by treatment with U73122 or the bombesin BB2 receptor antagonist [D-Phe(6), des-Met(14)]bombesin-(6-14) ethylester. A Fluorometric Imaging Plate Reader (FLIPR) was used to measure Ca(2+) in cell populations. Neuromedin C was approximately 50-fold more potent than neuromedin B in elevating Ca(2+) in astrocytes and Chinese hamster ovary (CHO) cells expressing human bombesin BB2 receptors (hBB2-CHO). However, in CHO cells expressing the bombesin BB1 receptor hBB1-CHO, neuromedin B was 32-fold more potent than neuromedin C. [D-Phe(6), des-Met(14)]bombesin-(6-14) ethylester was a partial agonist in hBB1-CHO cells (E(max)=55%) but was a noncompetitive antagonist in both hBB2-CHO cells and astrocytes. These studies report the first identification of functional bombesin receptors on cultured human astrocytes and have demonstrated that the bombesin BB2 receptor contributes significantly to astrocyte physiology.
逆转录聚合酶链反应（RT-PCR）显示，在培养的人星形胶质细胞中存在蛙皮素BB2受体mRNA，但不存在蛙皮素BB1受体或蛙皮素BB3受体mRNA。在全细胞电流和电压钳记录中，神经介素C使人类星形胶质细胞超极化，并增加了单个星形胶质细胞内的游离钙离子浓度（[Ca2+]i）。用神经介素C处理导致[Ca2+]i的升高比神经介素B引发的升高幅度更大、更频繁，分别有96%和78%的细胞做出反应。用U73122或蛙皮素BB2受体拮抗剂[D-Phe(6)，des-Met(14)]蛙皮素-(6-14)乙酯处理可显著抑制神经介素C的刺激作用。使用荧光成像板读数器（FLIPR）测量细胞群体中的[Ca2+]i。在星形胶质细胞和表达人蛙皮素BB2受体（hBB2-CHO）的中国仓鼠卵巢（CHO）细胞中，神经介素C在升高[Ca2+]i方面的效力比神经介素B高约50倍。然而，在表达蛙皮素BB1受体的hBB1-CHO细胞中，神经介素B的效力比神经介素C高32倍。[D-Phe(6)，des-Met(
