Details

Autor(en) / Beteiligte

• Fiacco, Todd A.
• Agulhon, Cendra
• Taves, Sarah R.
• Petravicz, Jeremy
• Casper, Kristen B.
• Dong, Xinzhong
• Chen, Ju
• McCarthy, Ken D.

Titel

Selective Stimulation of Astrocyte Calcium In Situ Does Not Affect Neuronal Excitatory Synaptic Activity

Ist Teil von

• Neuron (Cambridge, Mass.), 2007-05, Vol.54 (4), p.611-626

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2007

Quelle

MEDLINE

Beschreibungen/Notizen

• Astrocytes are considered the third component of the synapse, responding to neurotransmitter release from synaptic terminals and releasing gliotransmitters—including glutamate—in a Ca 2+-dependent manner to affect neuronal synaptic activity. Many studies reporting astrocyte-driven neuronal activity have evoked astrocyte Ca 2+ increases by application of endogenous ligands that directly activate neuronal receptors, making astrocyte contribution to neuronal effect(s) difficult to determine. We have made transgenic mice that express a Gq-coupled receptor only in astrocytes to evoke astrocyte Ca 2+ increases using an agonist that does not bind endogenous receptors in brain. By recording from CA1 pyramidal cells in acute hippocampal slices from these mice, we demonstrate that widespread Ca 2+ elevations in 80%–90% of stratum radiatum astrocytes do not increase neuronal Ca 2+, produce neuronal slow inward currents, or affect excitatory synaptic activity. Our findings call into question the developing consensus that Ca 2+-dependent glutamate release by astrocytes directly affects neuronal synaptic activity in situ.