Spontaneous astrocytic Ca2+ oscillations in situ drive NMDAR-mediated neuronal excitation

Abstract

Astrocytes respond to chemical, electrical and mechanical stimuli with transient increases in intracellular calcium concentration ([Ca2+]i). We now show that astrocytes in situ display intrinsic [Ca2+]i oscillations that are not driven by neuronal activity. These spontaneous astrocytic oscillations can propagate as waves to neighboring astrocytes and trigger slowly decaying NMDA receptor-mediated inward currents in neurons located along the wave path. These findings show that astrocytes in situ can act as a primary source for generating neuronal activity in the mammalian central nervous system.

4-hexylresorcinol exerts antitumor effects via suppression of calcium oscillation and its antitumor effects are inhibited by calcium channel blockers

“…The gene expression of ionotropic glutamate receptors was decreased by 4-HR application (data not shown). Glutamate receptor is related to calcium oscillation (27,28) and OSCC highly expresses glutamate receptor (29). However, the glutamate receptor-related hypothesis remains to be confirmed in further experimental studies.…”

Morphological plasticity of astroglia: Understanding synaptic microenvironment

“…A growing body of experimental evidence suggests that astrocyte signaling can, at least in certain conditions, influence excitatory synaptic transmission and its use‐dependent plasticity in a Ca 2+ ‐dependent manner (Henneberger et al, 2010; Jourdain et al, 2007; Min and Nevian, 2012; Navarrete et al, 2012; Parri et al, 2001; Perea and Araque, 2007). This does not necessarily imply that elegant experimental manipulations with astroglial Ca 2+ within a certain dynamic range by triggering certain cellular cascades should reproduce such effects (Agulhon et al, 2010; Fiacco et al, 2007; Petravicz et al, 2008) (see (Rusakov et al, 2014; Volterra et al, 2014) for discussion).…”

Modulation of intercellular calcium signaling in astrocytes by extracellular calcium and magnesium

“…Mechanisms proposed for these physiological and pathological effects have primarily focused on the modulation of neuronal ion channels and receptors. However, there is growing evidence that astrocytes play an active role in neuronal excitability and synaptic function Araque et al, 1999;Parri et al, 2001). Given that the spatial and temporal characteristics of intercellular Ca 2ϩ waves in astrocytes are very similar to those of spreading depression, the spreading oligemia of migraine, and the spread of some types of seizures (Charles, 1998), it is appealing to speculate that extracellular Ca 2ϩ and Mg 2ϩ may be involved in these phenomena via their effects on astrocyte Ca 2ϩ signaling and ATP release.…”

“…Astrocyte Ca 2ϩ waves may occur spontaneously or may be evoked by a variety of stimuli including mechanical stimulation, electrical stimulation, or neurotransmitters (Charles, 1998). In addition to being a pathway for communication among astrocytes, Ca 2ϩ waves have been shown to be a pathway for bidirectional signaling between astrocytes and multiple other cell types, including neurons (Araque et al, 1998;Kang et al, 1998;Parri et al, 2001), microglia (Schipke et al, 2002), and vascular endothelial cells (Leybaert et al, 1998;Paemeleire and Leybaert, 2000).…”