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Different mechanisms promote astrocyte Ca2+ waves and spreading depression in the mouse neocortex

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Item Type:Article
Title:Different mechanisms promote astrocyte Ca2+ waves and spreading depression in the mouse neocortex
Creators Name:Peters, O. and Schipke, C.G. and Hashimoto, Y. and Kettenmann, H.
Abstract:Cortical spreading depression (CSD) is thought to play an important role in different pathological conditions of the human brain. Here we investigated the interaction between CSD and Ca2+ waves within the astrocyte population in slices from mouse neocortex (postnatal days 10-14). After local KCl ejection as a trigger for CSD, we recorded the propagation of Ca2+ increases within a large population of identified astrocytes in synchrony with CSD measured as intrinsic optical signal (IOS) or negative DC-potential shift. The two events spread with 39.2 +/- 3.3 mum/sec until the IOS and negative DC-potential shift decayed after approximately 1 mm. However, the astrocyte Ca2+ wave continued to propagate for up to another 500 microm but with a reduced speed of 18.3 +/- 2.5 microm/sec that is also typical for glial Ca2+ waves in white matter or culture. While blocking CSD using MK-801 (40 microm), an NMDA-receptor antagonist, the astrocyte Ca2+ wave persisted with a reduced speed (13.2 +/- 1.5 microm/sec). The specific gap junction blocker carbenoxolon (100 microm) did not prevent CSD but decelerated the speed (2.9 +/- 0.9 microm/sec) of the astrocyte Ca2+ wave in the periphery of CSD. We also found that interfering with intracellular astrocytic Ca2+ signaling by depletion of internal Ca2+ stores does not affect the spread of the IOS. We conclude that CSD determines the velocity of an accompanying astrocytic Ca2+ response, but the astrocyte Ca2+ wave penetrates a larger territory and by this represents a self-reliant phenomenon with a different mechanism of propagation.
Keywords:Glia, Neocortex, Gap Junctions, Intrinsic Optical Signals, Migraine, Stroke, Animals, Mice
Source:Journal of Neuroscience
Publisher:Society for Neuroscience
Page Range:9888-9896
Date:29 October 2003
Additional Information:Copyright (c) 2003 by The Society for Neuroscience
Official Publication:http://www.jneurosci.org/cgi/content/abstract/23/30/9888
PubMed:View item in PubMed

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