Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Hippocampal Short- and Long-Term Plasticity Not Modulated by Astrocyte Signaling



Science 5 March 2010: Vol. 327. no. 5970, pp. 1250 - 1254

Hippocampal Short- and Long-Term Plasticity Are Not Modulated by Astrocyte Ca2+ Signaling

Cendra Agulhon,1 Todd A. Fiacco,2 Ken D. McCarthy1

1 Department of Pharmacology, University of North Carolina at Chapel Hill, Genetic Medicine Building, CB 7365, Chapel Hill, NC 27599, USA.
2 Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521, USA.


The concept that astrocytes release neuroactive molecules (gliotransmitters) to affect synaptic transmission has been a paradigm shift in neuroscience research over the past decade. This concept suggests that astrocytes, together with pre- and postsynaptic neuronal elements, make up a functional synapse. Astrocyte release of gliotransmitters (for example, glutamate and adenosine triphosphate) is generally accepted to be a Ca2+-dependent process. We used two mouse lines to either selectively increase or obliterate astrocytic Gq G protein–coupled receptor Ca2+ signaling to further test the hypothesis that astrocytes release gliotransmitters in a Ca2+-dependent manner to affect synaptic transmission. Neither increasing nor obliterating astrocytic Ca2+ fluxes affects spontaneous and evoked excitatory synaptic transmission or synaptic plasticity. Our findings suggest that, at least in the hippocampus, the mechanisms of gliotransmission need to be reconsidered.

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