The influence of long-term potentiation on the spatial relationship between astrocyte processes and potentiated synapses in the dentate gyrus neuropil of rat brain

Wenzel, J; Lammert, Grit; Meyer, U; Krug, Manfred

doi:10.1016/0006-8993(91)91222-m

Cited by 136 publications

(83 citation statements)

References 42 publications

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“…Although in vivo imaging revealed limited motility of astrocytic processes (Nimmerjahn et al, 2005), neuronal activity may upregulate their motility. Indeed, a previous study reported synaptic recruitment of astrocytic processes in longterm potentiation (Wenzel et al, 1991). Two-photon imaging of multiple neural components in combination with manipulations of synaptic efficacy will reveal whether the contact-dependent, local signaling system described here also functions in the mature neuron-glia network.…”

Section: Discussionmentioning

confidence: 75%

Direct Astrocytic Contacts Regulate Local Maturation of Dendritic Spines

Nishida¹,

Okabe²

2007

J. Neurosci.

237

230

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Astrocytes contribute on both development and function of synapses, but it remains unclear whether direct astrocytic contacts regulate development of individual synapses. Two-photon time-lapse imaging of astrocytic and dendritic protrusive activity revealed the correlation of astrocytic contacts with both lifetime and morphological maturation of dendritic protrusions. Astrocytic motility was essential in maturation of spines, because its suppression by manipulating Rac1-dependent signaling in astrocytes resulted in induction of longer, filopodia-like dendritic protrusions. Manipulation of ephrin/Eph-dependent neuron–astrocyte signaling suggested involvement of this signaling pathway in astrocyte-dependent stabilization of newly generated dendritic protrusions. Our data support a model in which astrocytic protrusive activity in development acts as a key local regulator for stabilization of individual dendritic protrusions and subsequent maturation into spines.

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Section: Discussionmentioning

confidence: 75%

Direct Astrocytic Contacts Regulate Local Maturation of Dendritic Spines

Nishida¹,

Okabe²

2007

J. Neurosci.

237

230

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“…Dendritic spine density is increased on pyramidal cells (Woolley et al, 1990), whereas astrocyte volume becomes lower in area CA1 of the hippocampus during proestrus, a time when estrogen levels peak during the reproductive cycle (Klintsova et al, 1995). Structural changes in spines and astrocytes have also been reported to take place after LTP induction (Wenzel et al, 1991;Segal, 2005), experimental models of epilepsy (Hawrylak et al, 1993;McKinney, 2005;Zha et al, 2005), and when rodents are reared in an enriched environment (Berman et al, 1996;Jones and Greenough, 1996;Soffie et al, 1999). Astrocytes also modulate synaptic efficacy of magnocellular neurons of the supraoptic nucleus of the hypothalamus by extending and retracting their processes.…”

Section: Discussionmentioning

confidence: 99%

Cooperative Astrocyte and Dendritic Spine Dynamics at Hippocampal Excitatory Synapses

Haber¹,

Zhou²,

Murai³

2006

J. Neurosci.

371

349

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Accumulating evidence is redefining the importance of neuron-glial interactions at synapses in the CNS. Astrocytes form "tripartite" complexes with presynaptic and postsynaptic structures and regulate synaptic transmission and plasticity. Despite our understanding of the importance of neuron-glial relationships in physiological contexts, little is known about the structural interplay between astrocytes and synapses. In the past, this has been difficult to explore because studies have been hampered by the lack of a system that preserves complex neuron-glial relationships observed in the brain. Here we present a system that can be used to characterize the intricate relationship between astrocytic processes and synaptic structures in situ using organotypic hippocampal slices, a preparation that retains the three-dimensional architecture of astrocyte-synapse interactions. Using time-lapse confocal imaging, we demonstrate that astrocytes can rapidly extend and retract fine processes to engage and disengage from motile postsynaptic dendritic spines. Surprisingly, astrocytic motility is, on average, higher than its dendritic spine counterparts and likely relies on actin-based cytoskeletal reorganization. Changes in astrocytic processes are typically coordinated with changes in spines, and astrocyte-spine interactions are stabilized at larger spines. Our results suggest that dynamic structural changes in astrocytes help control the degree of neuron-glial communication at hippocampal synapses.

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“…Chronic whisker stimulation induced structural changes in PAPs enhancing synaptic PAP coverage, as well as local glutamate transporter expression, in the barrel cortex of adult mice (Genoud et al, 2006). Inducing long‐term potentiation (LTP) in adult rats in vivo also leads to PAP structural plasticity in the dentate gyrus of the hippocampus (Wenzel et al, 1991). In the amygdala, however, only ∼50% of synapses are contacted by astrocytic processes which cover only ∼20% of the synaptic circumvent (Ostroff et al, 2014).…”

Section: Current Methods To Monitor Fine Astrocyte Morphology: Promismentioning

confidence: 99%

Morphological plasticity of astroglia: Understanding synaptic microenvironment

Heller

Rusakov

2015

Glia

133

137

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Memory formation in the brain is thought to rely on the remodeling of synaptic connections which eventually results in neural network rewiring. This remodeling is likely to involve ultrathin astroglial protrusions which often occur in the immediate vicinity of excitatory synapses. The phenomenology, cellular mechanisms, and causal relationships of such astroglial restructuring remain, however, poorly understood. This is in large part because monitoring and probing of the underpinning molecular machinery on the scale of nanoscopic astroglial compartments remains a challenge. Here we briefly summarize the current knowledge regarding the cellular organisation of astroglia in the synaptic microenvironment and discuss molecular mechanisms potentially involved in use‐dependent astroglial morphogenesis. We also discuss recent observations concerning morphological astroglial plasticity, the respective monitoring methods, and some of the newly emerging techniques that might help with conceptual advances in the area. GLIA 2015;63:2133–2151

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The influence of long-term potentiation on the spatial relationship between astrocyte processes and potentiated synapses in the dentate gyrus neuropil of rat brain

Cited by 136 publications

References 42 publications

Direct Astrocytic Contacts Regulate Local Maturation of Dendritic Spines

Direct Astrocytic Contacts Regulate Local Maturation of Dendritic Spines

Cooperative Astrocyte and Dendritic Spine Dynamics at Hippocampal Excitatory Synapses

Morphological plasticity of astroglia: Understanding synaptic microenvironment

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