Plasticity of perisynaptic astroglia during synaptogenesis in the mature rat hippocampus

  title={Plasticity of perisynaptic astroglia during synaptogenesis in the mature rat hippocampus},
  author={Mark R. Witcher and Sergei A. Kirov and Kristen M. Harris},
Astroglia are integral components of synapse formation and maturation during development. Less is known about how astroglia might influence synaptogenesis in the mature brain. Preparation of mature hippocampal slices results in synapse loss followed by recuperative synaptogenesis during subsequent maintenance in vitro. Hence, this model system was used to discern whether perisynaptic astroglial processes are similarly plastic, associating more or less with recently formed synapses in mature… 

Three‐dimensional relationships between perisynaptic astroglia and human hippocampal synapses

It is suggested that perisynaptic astroglial processes associate with synapses in human hippocampus in a manner similar to model systems and are disrupted by severe MTLE pathology.

Pre-existing astrocytes form functional perisynaptic processes on neurons generated in the adult hippocampus

Results indicate that pre-existing astrocytes remodel their processes to ensheathe synapses of adult-born neurons and participate to the functional and structural integration of these cells into the hippocampal network.

The ultrastructure of perisynaptic glia in the nucleus tractus solitarii of the adult rat: Comparison between single synapses and multisynaptic arrangements

The organization of astroglia in the Nucleus Tractus Solitarii (NTS), a sensory nucleus located in the caudal medulla, is investigated, finding that NTS glutamatergic synapses were not entirely surrounded by glia.

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The astrocytic perisynaptic processes act as an ‘astroglial cradle’ essential for synaptogenesis, maturation, isolation and maintenance of synapses, representing the fundamental mechanism contributing to synaptic connectivity, synaptic plasticity and information processing in the nervous system.

Synapses lacking astrocyte appear in the amygdala during consolidation of pavlovian threat conditioning

Examination of LA synapses after either threat conditioning or conditioned inhibition in adult rats suggests that contact with astrocytic processes opposes synapse growth during memory consolidation.

Why are Astrocytes Important?

Astroglial cells contribute to neuropathologies through mounting complex defensive programme generally known as reactive astrogliosis and are indispensible for glutamatergic and γ-aminobutyrate-ergic synaptic transmission being the supplier of neurotransmitters precursor glutamine via an astrocytic/neuronal cycle.

Neuroglial Plasticity at Striatal Glutamatergic Synapses in Parkinson's Disease

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Synaptic potentiation induces increased glial coverage of excitatory synapses in CA1 hippocampus

Recon reconstructions of synapses reveal dynamic, activity‐dependent interactions between glial processes and pre‐ and postsynaptic partners and suggest that glia can participate in activity‐induced structural synapse remodeling.



Timing of neuronal and glial ultrastructure disruption during brain slice preparation and recovery in vitro

Hippocampal slices often have more synapses than perfusion‐fixed hippocampus, but the cause of this synaptogenesis is unclear, and structural changes during slice preparation and recovery in vitro suggest widespread neurotransmitter release.

Synaptogenesis on mature hippocampal dendrites occurs via filopodia and immature spines during blocked synaptic transmission

Reconstruction from serial section electron microscopy suggests that synaptogenesis and spine formation are readily initiated under conditions of reduced activity in the mature brain.

Slices Have More Synapses than Perfusion-Fixed Hippocampus from both Young and Mature Rats

It is suggested that spines form in response to the loss of synaptic activity when slices are removed from the rest of the brain and during the subsequent 1 hr recovery period, which is the longest time investigated.

Synaptogenesis Via Dendritic Filopodia in Developing Hippocampal Area CA1

The concurrence of primarily shaft and filopodial synapses in the first postnatal week suggests that Filopodia recruit shaft synapses that later give rise to spines through a process of outgrowth.

Role for glia in synaptogenesis

It is proposed that astrocytes should not be viewed primarily as support cells, but rather as cells that actively control the structural and functional plasticity of synapses in developing and adult organisms.

The excitatory neurotransmitter glutamate causes filopodia formation in cultured hippocampal astrocytes

The excitatory neurotransmitter glutamate induces an increase in the number of filopodia on the surface of astrocytes cultured from the neonatal rat hippocampus, associated with a receptor‐mediated event that is activated to a lesser degree by the quisqualate and kainate, but not NMDA receptors.

Three-Dimensional Relationships between Hippocampal Synapses and Astrocytes

Recent studies show that glutamate transporter-mediated currents occur in astrocytes when glutamate is released from hippocampal synapses. These transporters remove excess glutamate from the