Astrocyte calcium microdomains are inhibited by Bafilomycin A1 and cannot be replicated by low-level Schaffer collateral stimulation in situ

Sun, Minwei; Devaraju, Prakash; Xie, Alison Xiaoqiao; Holman, Isabelle; Samones, Emmelyn; Murphy, Thomas R.; Fiacco, Todd A.

doi:10.1016/j.ceca.2013.10.004

Cited by 33 publications

(30 citation statements)

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“…A recent study showed that enhanced or blocked neuronal action potentials did not change astrocytic spontaneous microdomain Ca 2+ elevations, although the frequency of astrocyte Ca 2+ events largely decreased when miniature neurotransmitter release was blocked by bafilomycin A1. This work suggests that astrocytic Ca 2+ elevations are driven by neurotransmitter quantal release, but not by action potentials (Sun et al ., ), in agreement with previous studies (Parri et al ., ; Aguado et al ., ; Nett et al ., ). To our knowledge, no direct evidence has shown astrocyte‐like glial calcium oscillations in Drosophila , although cortex glia were shown to exhibit microdomain calcium oscillations (Melom & Littleton, ).…”

Section: Discussionmentioning

confidence: 98%

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Liu

Zhou

Yan

et al. 2014

Eur J of Neuroscience

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Astrocyte-like glial cells are abundant in the central nervous system of adult Drosophila and exhibit morphology similar to astrocytes of mammals. Previous evidence has shown that astrocyte-like glial cells are strongly associated with synapses in the antennal lobe (AL), the first relay of the olfactory system, where olfactory receptor neurons (ORNs) transmit information into projection neurons (PNs). However, the function of astrocyte-like glia in the AL remains obscure. In this study, using in vivo calcium imaging, we found that astrocyte-like glial cells exhibited spontaneous microdomain calcium elevations. Using simultaneous manipulation of glial activity and monitoring of neuronal function, we found that the astrocyte-like glial activation, but not ensheathing glial activation, could inhibit odor-evoked responses of PNs. Ensheathing glial cells are another subtype of glia, and are of functional importance in the AL. Electrophysiological experiments indicated that astrocyte-like glial activation decreased the amplitude and slope of excitatory postsynaptic potentials evoked through electrical stimulation of the antennal nerve. These results suggest that astrocyte-like glial cells may regulate olfactory processing through negative regulation of ORN-PN synaptic strength. Beyond the antennal lobe we observed astrocyte-like glial spontaneous calcium activities in the ventromedial protocerebrum, indicating that astrocyte-like glial spontaneous calcium elevations might be general in the adult fly brain. Overall, our study demonstrates a new function for astrocyte-like glial cells in the physiological modulation of olfactory information transmission, possibly through regulating ORN-PN synapse strength.

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Section: Discussionmentioning

confidence: 98%

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Liu

Zhou

Yan

et al. 2014

Eur J of Neuroscience

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“…We have previously shown that using these parameters, EFS-evoked endfoot Ca 2þ elevations and associated changes in arteriolar diameter are abolished in the presence of tetrodotoxin 15 indicating that these phenomena depend on the generation of neuronal action potentials. Throughout all recordings, brain slices were continually superfused with aerated aCSF (32)(33)(34) C) containing the thromboxane A 2 analog, 9,11 di-dideoxy-11a,9a-epoxymethanoprostaglandin F 2a (U46619, 100 nM) to induce a comparable intermediate level of arteriolar tone in brain slices from control and SAH animals. 15,17 Ionomycin (10 mM) and CaCl 2 (20 mM) were added to the bath at the end of each experiment to obtain maximal fluorescence.…”

Section: Rat Sah Modelmentioning

confidence: 99%

“…Bafilomycin depletes both neuronal and astroglial vesicles of transmitter and has been shown to inhibit Ca 2þ signals in the fine processes of hippocampal astrocytes. [33][34][35] Brain slices were exposed to bafilomycin for 4 h at room temperature prior to imaging. Vehicle-treated (DMSO: 1:1000 dilution in aCSF) brain slices served as time controls for these experiments.…”

Section: Sah-induced Ehacss Occur Independent Of Neurotransmitter Relmentioning

confidence: 99%

Purinergic signaling triggers endfoot high-amplitude Ca²⁺ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

Pappas

Koide

Wellman

2016

J Cereb Blood Flow Metab

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Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca 2þ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca 2þ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca 2þ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting G q -coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca 2þ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling.

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“…Further, astrocytes respond to neuronal activity with complex and variable patterns of Ca 2+ release (Bernardinelli et al, 2011). Depending on the pattern of synaptic activity or the presence of neuromodulators, these events may be constrained to a single astrocytic process or spread throughout a cell and even to adjacent astrocytes (Bernardinelli et al, 2011, Sun et al, 2014. These qualities endow astrocytes with the ability to regulate LTP and LTD at all anatomical levels, from single synapse to network.…”

Section: Section 2 Astrocytes In Plasticity and Metaplasticitymentioning

confidence: 98%

Astrocyte-mediated metaplasticity in the hippocampus: Help or hindrance?

Jones

2015

Neuroscience

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Astrocyte calcium microdomains are inhibited by Bafilomycin A1 and cannot be replicated by low-level Schaffer collateral stimulation in situ

Cited by 33 publications

References 50 publications

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Purinergic signaling triggers endfoot high-amplitude Ca²⁺ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

Astrocyte-mediated metaplasticity in the hippocampus: Help or hindrance?

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Astrocyte calcium microdomains are inhibited by Bafilomycin A1 and cannot be replicated by low-level Schaffer collateral stimulation in situ

Cited by 33 publications

References 50 publications

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Astrocyte‐like glial cells physiologically regulate olfactory processing through the modification of ORN‐PN synaptic strength in Drosophila

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

Astrocyte-mediated metaplasticity in the hippocampus: Help or hindrance?

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Purinergic signaling triggers endfoot high-amplitude Ca²⁺ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage