title: Application of an optogenetic byway for perturbing neuronal activity via glial photostimulation.
abstract: Dynamic activity of glia has repeatedly been demonstrated, but if such activity is independent from neuronal activity, glia would not have any role in the information processing in the brain or in the generation of animal behavior. Evidence for neurons communicating with glia is solid, but the signaling pathway leading back from glial-to-neuronal activity was often difficult to study. Here, we introduced a transgenic mouse line in which channelrhodopsin-2, a light-gated cation channel, was expressed in astrocytes. Selective photostimulation of these astrocytes in vivo triggered neuronal activation. Using slice preparations, we show that glial photostimulation leads to release of glutamate, which was sufficient to activate AMPA receptors on Purkinje cells and to induce long-term depression of parallel fiber-to-Purkinje cell synapses through activation of metabotropic glutamate receptors. In contrast to neuronal synaptic vesicular release, glial activation likely causes preferential activation of extrasynaptic receptors that appose glial membrane. Finally, we show that neuronal activation by glial stimulation can lead to perturbation of cerebellar modulated motor behavior. These findings demonstrate that glia can modulate the tone of neuronal activity and behavior. This animal model is expected to be a potentially powerful approach to study the role of glia in brain function.
authors.affiliation: Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki 444-8787, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Sasaki
authors.forename: Kaoru
authors.initials: K
authors.lastname: Beppu
authors.forename: Kenji F
authors.initials: KF
authors.lastname: Tanaka
authors.forename: Yugo
authors.initials: Y
authors.lastname: Fukazawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shigemoto
authors.forename: Ko
authors.initials: K
authors.lastname: Matsui
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology; D000075402:Channelrhodopsins; D018698:Glutamic Acid / Q000378:metabolism; D036881:Long-Term Synaptic Depression / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D009434:Neural Pathways / Q000502:physiology; D009457:Neuroglia / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D062308:Optogenetics; D010775:Photic Stimulation; D011689:Purkinje Cells / Q000502:physiology; D018091:Receptors, AMPA / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D000075402:Channelrhodopsins; D018091:Receptors, AMPA; D018698:Glutamic Acid