Astrocytic GPCR-Induced Ca Signaling Is Not Causally Related to Local Cerebral Blood Flow Changes.

Activation of Gq-type G protein-coupled receptors (GPCRs) gives rise to large cytosolic Ca elevations in astrocytes. Previous in vitro and in vivo studies have indicated that astrocytic Ca elevations are closely associated with diameter changes in the nearby blood vessels, which astrocytes enwrap with their endfeet. However, the causal relationship between astrocytic Ca elevations and blood vessel diameter changes has been questioned, as mice with diminished astrocytic Ca signaling show normal sensory hyperemia.

Transcranial Direct Current Stimulation (tDCS) Induces Adrenergic Receptor-Dependent Microglial Morphological Changes in Mice.

Transcranial direct current stimulation (tDCS) has been reported for its beneficial effects on memory formation and various brain disorders. While the electrophysiological readout of tDCS effects is subtle, astrocytes have been demonstrated to elicit Ca elevations during tDCS in a rodent model. This study aimed to elucidate the effects of tDCS on another major glial cell type, microglia, by histology and imaging.

Volume transmission signalling via astrocytes.

The influence of astrocytes on synaptic function has been increasingly studied, owing to the discovery of both gliotransmission and morphological ensheathment of synapses. While astrocytes exhibit at best modest membrane potential fluctuations, activation of G-protein coupled receptors (GPCRs) leads to a prominent elevation of intracellular calcium which has been reported to correlate with gliotransmission. In this review, the possible role of astrocytic GPCR activation is discussed as a trigger to promote synaptic plasticity, by affecting synaptic receptors through gliotransmitters.

Astrocyte calcium signaling transforms cholinergic modulation to cortical plasticity in vivo.

Global brain state dynamics regulate plasticity in local cortical circuits, but the underlying cellular and molecular mechanisms are unclear. Here, we demonstrate that astrocyte Ca(2+) signaling provides a critical bridge between cholinergic activation, associated with attention and vigilance states, and somatosensory plasticity in mouse barrel cortex in vivo. We investigated first whether a combined stimulation of mouse whiskers and the nucleus basalis of Meynert (NBM), the principal source of cholinergic innervation to the cortex, leads to enhanced whisker-evoked local field potential.

In vivo intracellular recording suggests that gray matter astrocytes in mature cerebral cortex and hippocampus are electrophysiologically homogeneous.

Previous anatomical and in vitro electrophysiology studies suggest that astrocytes are heterogeneous in physiology, morphology, and biochemical content. However, the extent to which this diversity applies to in vivo conditions is largely unknown. To characterize and classify the physiological and morphological properties of cerebral cortical and hippocampal astrocytes in the intact brain, we performed in vivo intracellular recordings from single astrocytes using anesthetized mature rats.

Neurons associated with the flip-flop activity in the lateral accessory lobe and ventral protocerebrum of the silkworm moth brain.

The lateral accessory lobe (LAL) and the ventral protocerebrum (VPC) are a pair of symmetrical neural structures in the insect brain. The LAL-VPC is regarded as the major target of olfactory responding neurons as well as the control center for olfactory-evoked sequential zigzag turns. Previous studies of the silkworm moth Bombyx mori showed that these turns are controlled by long-lasting anti-phasic activities of the flip-flopping descending neurons with dendrites in the LAL-VPC.

Intracellular labeling of single cortical astrocytes in vivo.

Glial cells have traditionally been considered to play supportive roles in the central nervous system. As recent experimental evidence suggests glial cells' participation in neural information processing, there has been a need to monitor the physiology of glial cells in vivo in the matured brain. Concurrently, identification and classification of the recorded glial cells is essential as there are at least several different kinds of glial cells.