Activation of Muscarinic and of α1-Adrenergic Receptors on Astrocytes Results in the Accumulation of Inositol Phosphates |
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Authors: | Brian Pearce Martin Cambray-Deakin Christine Morrow Jill Grimble Sean Murphy |
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Institution: | Brain Research Group, Biology Department, The Open University, Milton Keynes, England |
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Abstract: | Astrocyte-enriched cultures prepared from the newborn rat cortex incorporated 3H]myo-inositol into intracellular free inositol and inositol lipid pools. Noradrenaline and carbachol stimulated the turnover of these pools resulting in an increased accumulation of intracellular 3H]inositol phosphates. The effects of noradrenaline and carbachol were dose-dependent and blocked by specific alpha 1-adrenergic and muscarinic cholinergic receptor antagonists, respectively. The increase in 3H]inositol phosphate accumulation caused by these receptor antagonists was virtually unchanged when cultures were incubated in Ca2+-free medium, but was abolished when EGTA was also present in the Ca2+-free medium. Cultures of meningeal fibroblasts, the major cell type contaminating the astrocyte cultures, also accumulated 3H]myo-inositol, but no increased accumulation of 3H]inositol phosphates was found in response to either noradrenaline or carbachol. |
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Keywords: | Astrocytes Muscarinic receptors α1-Adrenergic receptors [3H]Inositol phosphate accumulation |
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