Identification and characterisation of functional bombesin receptors in human astrocytes

European Journal of Pharmacology
Sarah MasonShaun McNulty

Abstract

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+)](i)) in single astrocytes. Treatment with neuromedin C caused larger and more frequent increases in [Ca(2+)](i) 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+)](i) in cell populations. Neuromedin C was approximately 50-fold more potent than neuromedin B in elevating [Ca(2+)](i) 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 agonis...Continue Reading

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Citations

Jan 20, 2018·Physiological Reviews·Alexei Verkhratsky, Maiken Nedergaard

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