The role of Ca2+ in the generation of spontaneous astrocytic Ca2+ oscillations
| Autor: | Vincenzo Crunelli, H. R. Parri |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Boron Compounds
Patch-Clamp Techniques In Vitro Techniques Biology Methoxyhydroxyphenylglycol chemistry.chemical_compound Thalamus Caffeine medicine Animals Drug Interactions Calcium Signaling Enzyme Inhibitors Protein kinase C Aniline Compounds Microscopy Confocal Phospholipase C Ryanodine Ryanodine receptor Thimerosal General Neuroscience Dioxolanes 3-Pyridinecarboxylic acid 1 4-dihydro-2 6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)- Methyl ester Inositol trisphosphate receptor Rats Calcium Channel Agonists medicine.anatomical_structure Animals Newborn Xanthenes Biochemistry chemistry Purines Metabotropic glutamate receptor Astrocytes Anti-Infective Agents Local Biophysics Neuroglia Calcium Cyclopiazonic acid Astrocyte |
| Zdroj: | Neuroscience. 120:979-992 |
| ISSN: | 0306-4522 |
| DOI: | 10.1016/s0306-4522(03)00379-8 |
| Popis: | Astrocytes in the rat thalamus display spontaneous [Ca(2+)](i) oscillations that are due to intracellular release, but are not dependent on neuronal activity. In this study we have investigated the mechanisms involved in these spontaneous [Ca(2+)](i) oscillations using slices loaded with Fluo-4 AM (5 microM) and confocal microscopy. Bafilomycin A1 incubation had no effect on the number of spontaneous [Ca(2+)](i) oscillations indicating that they were not dependent on vesicular neurotransmitter release. Oscillations were also unaffected by ryanodine. Phospholipase C (PLC) inhibition decreased the number of astrocytes responding to metabotropic glutamate receptor (mGluR) activation but did not reduce the number of spontaneously active astrocytes, indicating that [Ca(2+)](i) increases are not due to membrane-coupled PLC activation. Spontaneous [Ca(2+)](i) increases were abolished by an IP3 receptor antagonist, whilst the protein kinase C (PKC) inhibitor chelerythrine chloride prolonged their duration, indicating a role for PKC and inositol 1,4,5,-triphosphate receptor activation. BayK8644 increased the number of astrocytes exhibiting [Ca(2+)](i) oscillations, and prolonged the responses to mGluR activation, indicating a possible effect on store-operated Ca(2+) entry. Increasing [Ca(2+)](o) increased the number of spontaneously active astrocytes and the number of transients exhibited by each astrocyte. Inhibition of the endoplasmic reticulum Ca(2+) ATPase by cyclopiazonic acid also induced [Ca(2+)](i) transients in astrocytes indicating a role for cytoplasmic Ca(2+) in the induction of spontaneous oscillations. Incubation with 20 microM Fluo-4 reduced the number of astrocytes exhibiting spontaneous increases. This study indicates that Ca(2+) has a role in triggering Ca(2+) release from an inositol 1,4,5,-triphosphate sensitive store in astrocytes during the generation of spontaneous [Ca(2+)](i) oscillations. |
| Databáze: | OpenAIRE |
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