Selective stimulation of astrocyte calcium in situ does not affect neuronal excitatory synaptic activity.
Neuron
; 54(4): 611-26, 2007 May 24.
Article
em En
| MEDLINE
| ID: mdl-17521573
ABSTRACT
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sinapses
/
Astrócitos
/
Cálcio
/
Células Piramidais
/
Transmissão Sináptica
Limite:
Animals
Idioma:
En
Revista:
Neuron
Ano de publicação:
2007
Tipo de documento:
Article