Table of Contents
The tripartite synapse:
Presynapse, Postsynapse, and Glia
Glial Categories
Glia Astrocytes positioned to regulate energy metabolism at synapses
Identifying Astrocytes in CNS Neuropil (synapses.bu.edu)
Interdigitating irregular shapes
Clearer cytoplasm than neurons
Glycogen Granules
(stored source of glucose)
Glucose at Astro-Synapses
Glycogen Granules
Distinguished from polyribosomes
Astrocytic intermediate filaments
3D relationship of astrocytic processes to hippocampal dendrite
and synaptic varicosities
Astrocyte Functions at Synpases
ASTROCYTIC PROCESSES IN HIPPOCAMPAL AREA CA1
Cortical Synapse-Glia (black ink)
Cortex is like hippocampus
Cerebellar Synapses are surrounded by astrocytic (Bergmann) Glia
Cerebellar Spine Synapses surrounded by glia
Cerebellar Spine Synapses are unlike Cortex and Hippocampus
Astrocyte-neuronal adhesion junction
SER at Astro-neuronal adhesion junctions
Neuronal-Astrocytic Nonsynaptic
Puncta Adherens Junctions
Tripartite Synapses: glia, the unacknowledged partner
Selective stimulation of glial cells
Mechanical stimulation of 1 astrocyte
Spread of intracellular calcium
Spread of calcium between astrocytes
Elevated Ca2+ in Glia
also increases neuronal Ca2+
Example effect of Glial Ca2+
wave on synaptic responses
Synaptic effects of Glial Stimulation
Astrocytes in synapse feedback
Wednesday
Bidirectional communication
Do astrocytes grow to active synapses that are releasing glutamate?
Control of Synapse Number by Glia
Synaptogenesis follows
Glia - genesis during development
Retinal Ganglion Cells in Culture
Synapse Number is greater with Glia
No Change in Vesicle Number per Synaptic Bouton
The extra synapses formed
with glia are functional
Synapse Current Density Increases
Glia do not alter the total content of synaptic proteins in neurons
Instead glia facilitate clustering of synaptic proteins into synaptic puncta (spots)
Summary
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