The role of Ca2+ in the generation of spontaneous astrocytic Ca2+ oscillations

Parri, H.R. and Crunelli, V. (2003). The role of Ca2+ in the generation of spontaneous astrocytic Ca2+ oscillations. Neuroscience, 120 (4), pp. 979-992.

Abstract

Astrocytes in the rat thalamus display spontaneous [Ca2+]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 [Ca2+]i oscillations using slices loaded with Fluo-4 AM (5 μM) and confocal microscopy. Bafilomycin A1 incubation had no effect on the number of spontaneous [Ca2+]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 [Ca2+]i increases are not due to membrane-coupled PLC activation. Spontaneous [Ca2+]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 [Ca2+]i oscillations, and prolonged the responses to mGluR activation, indicating a possible effect on store-operated Ca2+ entry. Increasing [Ca2+]o increased the number of spontaneously active astrocytes and the number of transients exhibited by each astrocyte. Inhibition of the endoplasmic reticulum Ca2+ ATPase by cyclopiazonic acid also induced [Ca2+]i transients in astrocytes indicating a role for cytoplasmic Ca2+ in the induction of spontaneous oscillations. Incubation with 20 μM Fluo-4 reduced the number of astrocytes exhibiting spontaneous increases. This study indicates that Ca2+ has a role in triggering Ca2+ release from an inositol 1,4,5,-triphosphate sensitive store in astrocytes during the generation of spontaneous [Ca2+]i oscillations

Publication DOI: https://doi.org/10.1016/S0306-4522(03)00379-8
Divisions: Life & Health Sciences > Pharmacy
Life & Health Sciences
Uncontrolled Keywords: 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester,aniline Compounds,animals,animals, newborn,Anti-Infective agents, local,astrocytes,boron compounds,caffeine,calcium,calcium channel agonists,calcium signaling,dioxolanes,drug Interactions,enzyme inhibitors,Methoxyhydroxyphenylglycol,microscopy, confocal,Patch-Clamp techniques,purines,rats,ryanodine,thalamus,thimerosal,xanthenes,Ventrobasal thalamus,glia,development,Thalamocortical
Published Date: 2003-09-15
Authors: Parri, H.R. ( 0000-0002-1412-2688)
Crunelli, V.

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