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Pericellular innervation of neurons expressing abnormally hyperphosphorylated tau in the hippocampal formation of Alzheimer's disease patients.

Blazquez-Llorca L, Garcia-Marin V, Defelipe J - Front Neuroanat (2010)

Bottom Line: This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons.Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau.These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Circuitos Corticales (Centro de Tecnología Biomédica), Universidad Politécnica de Madrid Madrid, Spain.

ABSTRACT
Neurofibrillary tangles (NFT) represent one of the main neuropathological features in the cerebral cortex associated with Alzheimer's disease (AD). This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons. We have used immunocytochemical techniques and confocal microscopy reconstructions to examine the distribution of PHF-tau-immunoreactive (ir) cells, and their perisomatic GABAergic and glutamatergic innervations in the hippocampal formation and adjacent cortex of AD patients. Furthermore, correlative light and electron microscopy was employed to examine these neurons and the perisomatic synapses. We observed two patterns of staining in PHF-tau-ir neurons, pattern I (without NFT) and pattern II (with NFT), the distribution of which varies according to the cortical layer and area. Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau. At the electron microscope level, a normal looking neuropil with typical symmetric and asymmetric synapses was observed around PHF-tau-ir neurons. These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered.

No MeSH data available.


Related in: MedlinePlus

High magnification electron micrograph illustrating the neuropil around the PHF-tau-ir cell 7 also shown in Figure 14, where the soma has been pseudo-colored in blue. Asterisk, paired helical filaments stained for PHF-tau. Arrows indicate some synaptic contacts in the neuropil. Scale bar: 0.5 μm.
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Figure 15: High magnification electron micrograph illustrating the neuropil around the PHF-tau-ir cell 7 also shown in Figure 14, where the soma has been pseudo-colored in blue. Asterisk, paired helical filaments stained for PHF-tau. Arrows indicate some synaptic contacts in the neuropil. Scale bar: 0.5 μm.

Mentions: Finally, when we analyzed the neuropil surrounding PHF-tau-ir neurons it had a normal aspect, and no reactive glial processes nor abnormal looking dendrite or axonal profiles were observed. Furthermore, the typical symmetric synapses innervating the somata of pyramidal cells were preserved on the PHF-tau-ir neurons with either type I or II staining. In addition, in the neuropil adjacent to these cells normal looking symmetric and asymmetric synapses were also observed (Figures 14H–J and 15). These observations suggest that the synaptic connectivity around these neurons was apparently unaltered.


Pericellular innervation of neurons expressing abnormally hyperphosphorylated tau in the hippocampal formation of Alzheimer's disease patients.

Blazquez-Llorca L, Garcia-Marin V, Defelipe J - Front Neuroanat (2010)

High magnification electron micrograph illustrating the neuropil around the PHF-tau-ir cell 7 also shown in Figure 14, where the soma has been pseudo-colored in blue. Asterisk, paired helical filaments stained for PHF-tau. Arrows indicate some synaptic contacts in the neuropil. Scale bar: 0.5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2903190&req=5

Figure 15: High magnification electron micrograph illustrating the neuropil around the PHF-tau-ir cell 7 also shown in Figure 14, where the soma has been pseudo-colored in blue. Asterisk, paired helical filaments stained for PHF-tau. Arrows indicate some synaptic contacts in the neuropil. Scale bar: 0.5 μm.
Mentions: Finally, when we analyzed the neuropil surrounding PHF-tau-ir neurons it had a normal aspect, and no reactive glial processes nor abnormal looking dendrite or axonal profiles were observed. Furthermore, the typical symmetric synapses innervating the somata of pyramidal cells were preserved on the PHF-tau-ir neurons with either type I or II staining. In addition, in the neuropil adjacent to these cells normal looking symmetric and asymmetric synapses were also observed (Figures 14H–J and 15). These observations suggest that the synaptic connectivity around these neurons was apparently unaltered.

Bottom Line: This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons.Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau.These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Circuitos Corticales (Centro de Tecnología Biomédica), Universidad Politécnica de Madrid Madrid, Spain.

ABSTRACT
Neurofibrillary tangles (NFT) represent one of the main neuropathological features in the cerebral cortex associated with Alzheimer's disease (AD). This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons. We have used immunocytochemical techniques and confocal microscopy reconstructions to examine the distribution of PHF-tau-immunoreactive (ir) cells, and their perisomatic GABAergic and glutamatergic innervations in the hippocampal formation and adjacent cortex of AD patients. Furthermore, correlative light and electron microscopy was employed to examine these neurons and the perisomatic synapses. We observed two patterns of staining in PHF-tau-ir neurons, pattern I (without NFT) and pattern II (with NFT), the distribution of which varies according to the cortical layer and area. Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau. At the electron microscope level, a normal looking neuropil with typical symmetric and asymmetric synapses was observed around PHF-tau-ir neurons. These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered.

No MeSH data available.


Related in: MedlinePlus