Neurosciencecontents.kocw.net/KOCW/document/2015/chungnam/... · 2016-09-09 · 2007 Nature Neuroscience Tripartite Synapse - Considered a physical barrier to restrict spill over
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- evident with H&E at about 12-24 hrs after insult
2) 아급성 및 만성 신경세포손상(subacute and chronic neuronal injury = degeneration; 변성)
* trans-synaptic degeneration
3) 축삭반응(axonal reaction)
4) neuronal inclusions and intracytoplasmic deposits
(1) viral infections
(2) Lewy bodies in PD, Neurofibrillary tangles in AD
Acute neuronal injury: Neurons are vulnerable to cytotoxic stress. In acute neuronal injury, the cell shrinks, cytoplasm becomes deeply eosinophilic and nucleus appears
pyknotic—the so called “red dead” neuron. In acute hypoxic
encephalopathy, these changes are frequently observed in the cortex (layers III,V), hippocampus (CA1) and cerebellar Purkinje layer
Pyknosis, or karyopyknosis, is the irreversible
condensation of chromatin in the nucleus of a cell
undergoing necrosis or apoptosis.
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Chromatolysis (염색질용해, axonal reaction); When the axon of a neuron is cut or damaged,
1. The cell body swells2. The Nissl bodies disperse and move peripherally3. The nucleus is displaced peripherally in the cell
Pigment
Lipofuscin
melanin
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Cell processes (neurites)
Dendrite
Dedritic spine (가시돌기가시)
Mental retardation
Spines and the strucutural basis of memory
Synaptoneurosome
Polyribosome below
synapses in dendritic
spines
Fragile X mental
retardation protein
(FMRP)
Fragile X syndrome
William Greenough
It was worth the effort.
Axon
Axon hillock: nissl body (X)
분지양상: 축삭곁가지 (axon collateral)
종말가지 (telodendron)
Boutons terminal (신경종말, 종말단추)
축삭의 형질막: axolemma
축삭의 세포질: axoplasma, Nissl body,
golgi (X)
Initial segment: action potential (AP)
@ immunohistochemical markers ; neurofilament protein (NF), neuron specific enolase (NSE), synaptophysin NeuN
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Axon vs. dendrite
Neuroglia (신경아교세포)
Astrocyte
protoplasmic astrocyte
fibrous astrocyte
Oligodendrocyte
perineuronal satellite
cell
interfascicular cell
Microglia
Ependymal Cell
Schwann Cell
in peripheral nerve &
ganglion
Capsular (Satellite) Cell
in ganglion
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Astrocyte (별아교세포)
Physical support for neurons & Energy provision with Glucose uptake
Guiding for migratory neuron
Brain-blood barrier (BBB): regulation of blood flow
Homeostasis of ions (K) and transmitters (Glu, GABA)
Regulation of synapse function & neural activity
Neuronal progenitor from radial glia
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human astrocytes are larger and more complex than rodent and other primates
Heterogeinity of human astrocyte(1) Protoplasmic ; mostly in gray matter, branched process(2) Fibrous ; mostly in white matter, long-thin process(3) Radial astrocyte (glia)(4) Perivascular or Marginal astrocyte: pia mater(5) Velate astrocyte: cerebellum(6) Muller cells: retina(7) Bergmann glia: cerebellum(8) Ependymal cells
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Astrocytes are closely related to cerebral blood vessels
and synapses.
2007 Nature Neuroscience
Tripartite Synapse
- Considered a physical barrier to restrict spill over and diffusion of released molecules to ECS.
Microglial cells are highly active in the presumed resting state, continually surveying their microenvironment with extremely motile processes and ramifications. Synaptic pruning
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Microglia: Detrimental vs. Protective
Microglia activation pathway
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Oligodendrocyte
(희소돌기아교세포)
Small, lymphocyte-sized
nucleus with a clear halo ;
fried egg appearance
Function; production and
maintenance of the CNS
myelin
Perineuronal Satellite Cell
Interfascicular Cell
Myelin forming cell in CNS
- Myelin Sheath
Cho et al., 1997
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FIGURE 31-4: Premyelinating and myelinating oligodendrocytes in vivo. Representative images of (A) premyelinating oligodendrocytes from P6 mouse cortex, labeled with EGFP (in Plp -EGFP mice (Mallon et al., 2002) and PLP (Texas Red) or (B) a myelinating oligodendrocyte from mature mouse striatum labeled with EGFP (in Plp -EGFP mice). (Figure 4B reproduced from Mallon et al., 2002).
3. Minor dense line: PLP (jimpy mice), protein 0 (Trembler mice)
4. Cytoplasm of Schwann cell
* 융합하지 않은 면: MAG
Myelin Proteins
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Myelination in CNS
OLG
한세포가 담당하는 신경섬유의 숫자가 최대 60개
하나의 축삭중 여러 마디도가능
Node of Ranvier 존재
말이집틈새 존재
축삭간막이 없다
Ependymal cell
Epithelial Cell
lining ventricular surface
cilia and microvilli on luminal surface
simple cuboidal cell with round nucleus
Tanicyte
basal process, numerous in 3rd ventricle
Choroid Plexus Epithelial Cells
ion transporting cell: numerous mitochondria
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Tanycytes
Figure 25.5 Regeneration in peripheral nerves
1. Cut2. Distal portion degenerates3. Phagocytosed by Macrophages4. Debris is mostly cleared5. Proximal axon stump transforms into a growth cone6. Axon has regrown
Donor graftExercise
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Figure 25.6 Molecular and cellular responses that promote
peripheral nerve regeneration
Figure 25.11 Cellular response to injury in the CNS
MAG
Nogo
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Figure 25.7 Growth-promoting properties of peripheral nerve sheaths and
Schwann cells facilitate growth of damaged axons in the CNS
1. Optic nerve is CNS, therefore, would normally not regenerate through the optic nerve.
2. Now grow through the peripheral nerve graft to reach the SC, a normal target for retinal ganglion cells