Hippocampal short- and long-term plasticity are not modulated by astrocyte Ca2+ signaling.
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.
Agulhon
Cendra
C
Department of Pharmacology, University of North Carolina at Chapel Hill, Genetic Medicine Building, CB 7365, Chapel Hill, NC 27599, USA. cendra_agulhon@med.unc.edu
Fiacco
Todd A
TA
McCarthy
Ken D
KD
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D019706:Excitatory Postsynaptic Potentials; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D066298:In Vitro Techniques; D017774:Long-Term Potentiation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016202:N-Methylaspartate / Q000378:metabolism; D009473:Neuronal Plasticity; D009474:Neurons / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D009435:Synaptic Transmission
C470191:MrgA1 protein, mouse; D018377:Neurotransmitter Agents; D043562:Receptors, G-Protein-Coupled; D016202:N-Methylaspartate; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D002118:Calcium