Astrocytes modulate neural network activity by Ca²+-dependent uptake of extracellular K+.
Sci Signal
; 5(218): ra26, 2012 Apr 03.
Article
em En
| MEDLINE
| ID: mdl-22472648
ABSTRACT
Astrocytes are electrically nonexcitable cells that display increases in cytosolic calcium ion (Ca²+) in response to various neurotransmitters and neuromodulators. However, the physiological role of astrocytic Ca²+ signaling remains controversial. We show here that astrocytic Ca²+ signaling ex vivo and in vivo stimulated the Na+,K+-ATPase (Na+- and K+-dependent adenosine triphosphatase), leading to a transient decrease in the extracellular potassium ion (K+) concentration. This in turn led to neuronal hyperpolarization and suppressed baseline excitatory synaptic activity, detected as a reduced frequency of excitatory postsynaptic currents. Synaptic failures decreased in parallel, leading to an increase in synaptic fidelity. The net result was that astrocytes, through active uptake of K+, improved the signal-to-noise ratio of synaptic transmission. Active control of the extracellular K+ concentration thus provides astrocytes with a simple yet powerful mechanism to rapidly modulate network activity.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Astrócitos
/
Cálcio
/
Transmissão Sináptica
Limite:
Animals
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article