This work was supported by the Uehara Memorial Foundation of Japan (to ES) as well as the Whitehall Foundation, the National Institute of Neurological Disorders and Stroke and a Stein-Oppenheimer Endowment Award (to BSK).

EXPERIMENTAL PROCEDURES
The experimental procedure consists of two key parts that are described in a step wise manner below.
Part 1: PREPARING HIPPOCAMPAL ASTROCYTE CULTURES
Briefly, mixed hippocampal astrocyte-neuron cultures were prepared using a well established protocol1,2,3. We optimized the procedure to yield healthy cultured astrocytes. All the procedures listed below should be carried out in a sterile environment such as a ...

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It is well-established that astrocytes display intracellular calcium elevations. These occur spontaneously, can be triggered by neuronal activity or by application of agonists to activate receptors on the astrocyte surface11. One important and controversial issue is whether astrocyte intracellular calcium elevations can trigger the release of signaling molecules that activate receptors on neurons11, 12. This is controversial because there has been evidence for and against this view, as highlighted i...

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<td>VWR&#174; Micro Cover Slips, Round, No. 1</td>
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<td>VWR</td>
<td>48380-068</td>
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<td>Poly-D-lysine hydrobromide</td>
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<td>Sigma</td>
<td>P0899</td>
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<td>Laminin from Engelbreth-Holm-Swarm murine sarcoma basement membrane</td>
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<td>Sigma</td>
<td>L2020</td>
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<td>Earle&#x2019;s Balanced Salt Solution (EBSS) (1X), liquid</td>
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<td>Invitrogen</td>
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<td>Minimum Essential Medium (MEM) (1X), liquid Contains Earle's salts, but no L-glutamine or phenol red</td>
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<td>Invitrogen</td>
<td>51200-038</td>
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<td>Invitrogen</td>
<td>15140-122</td>
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<td>Sodium pyruvate solution</td>
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<td>Sigma</td>
<td>S8636</td>
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<td>HEPES solution 1 M</td>
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<td>H0887</td>
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<td>Reagent</td>
<td>Invitrogen</td>
<td>17502-048</td>
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<td>Horse Serum, Heat-Inactivated</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>26050-088</td>
<td>&nbsp;</td>
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<td>PAPAIN-022</td>
<td>Reagent</td>
<td>Worthington</td>
<td>LK003178</td>
<td>&nbsp;</td>
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<td>Neurobasal&#x2122; Medium (1X) Liquid without Phenol Red</td>
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<td>Invitrogen</td>
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<td>Reagent</td>
<td>Invitrogen</td>
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<td>P3911</td>
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<td>CaCl2 hexahydrate</td>
<td>Reagent</td>
<td>Sigma</td>
<td>21108</td>
<td>&nbsp;</td>
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<td>MgCl2 hexahydrate</td>
<td>Reagent</td>
<td>Sigma</td>
<td>M2670</td>
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<td>Reagent</td>
<td>Sigma</td>
<td>H3375</td>
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<td>D-(+)-glucose</td>
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<td>Sigma</td>
<td>G7528</td>
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<td>Fluo-4, AM 1 mM solution in DMSO</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>F-14217</td>
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<td>Pluronic&#174; F-127 20% solution in DMSO</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>P-3000MP</td>
<td>&nbsp;</td>
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<td>Immersion Oil TYPE DF</td>
<td>Microscope</td>
<td>Cargille</td>
<td>16242</td>
<td>&nbsp;</td>
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<td>Open chamber for 25 mm round coverslips, 100 &mu;l volume</td>
<td>Tool</td>
<td>WARNER Instruments</td>
<td>64-0362 (RC-21BDW)</td>
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<td>P-2 platform for Series 20 chambers, non-heater</td>
<td>Tool</td>
<td>WARNER Instruments</td>
<td>64-0278 (P-2)</td>
<td>&nbsp;</td>
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<td>FluoSpheres carboxylate-modified microspheres, 0.1 &mu;m, yellow-green fluorescent (505/515) 2% solids</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>F8803</td>
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measuring near plasma membrane and global intracellular calcium dynamics in astrocytes

The brain contains glial cells.  Astrocytes, a type of glial cell, have long been known to provide a passive supportive role to neurons. However, increasing evidence suggests that astrocytes may also actively participate in brain function through functional interactions with neurons.  However, many fundamental aspects of astrocyte biology remain controversial, unclear and/or experimentally unexplored. One important issue is the dynamics of intracellular calcium transients in astrocytes. This is relevant because calcium is well established as an important second messenger and because it has been proposed that astrocyte calcium elevations can trigger the release of transmitters from astrocytes. However, there has not been any detailed or satisfying description of near plasma membrane calcium signaling in astrocytes. Total internal reflection fluorescence (TIRF) microscopy is a powerful tool to analyze physiologically relevant signaling events within about 100 nm of the plasma membrane of live cells. Here, we use TIRF microscopy and describe how to monitor near plasma membrane and global intracellular calcium dynamics almost simultaneously. The further refinement and systematic application of this approach has the potential to inform about the precise details of astrocyte calcium signaling. A detailed understanding of astrocyte calcium dynamics may provide a basis to understand if, how, when and why astrocytes and neurons undergo calcium-dependent functional interactions.

Watch this Scientific Journal Video about Measuring Near Plasma Membrane and Global Intracellular Calcium Dynamics in Astrocytes at JoVE.com

Measuring Near Plasma Membrane and Global Intracellular Calcium Dynamics in Astrocytes

We describe how to measure near membrane and global intracellular calcium dynamics in cultured astrocytes using total internal reflection and epifluorescence microscopy.

The brain contains glial cells.  Astrocytes, a type of glial cell, have long been known to provide a passive supportive role to neurons. However, ...

measuring-near-plasma-membrane-global-intracellular-calcium-dynamics

Research

JoVE Journal

Biology

13.0K vues.  David Geffen School of Medicine, University of California, Los Angeles. Nous décrivons comment mesurer près de la membrane et la dynamique globale du calcium intracellulaire dans les astrocytes cultivés en utilisant la réflexion interne totale et de la microscopie à épifluorescence.