Activation of muscarinic and of alpha 1-adrenergic receptors on astrocytes results in the accumulation of inositol phosphates.
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.
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism*; D007700:Kinetics; D009638:Norepinephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000502:physiology*; D013403:Sugar Phosphates / Q000378:metabolism*; D014316:Tritium; D015016:Yohimbine / Q000494:pharmacology
D007295:Inositol Phosphates; D011942:Receptors, Adrenergic, alpha; D011976:Receptors, Muscarinic; D013403:Sugar Phosphates; D014316:Tritium; D015016:Yohimbine; D007294:Inositol; D001285:Atropine; D002217:Carbachol; D009638:Norepinephrine; D011224:Prazosin