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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

(A,B), (D,E), pairs of confocal images from the same section and field to illustrate the presence of GAT-1-ir axon terminals (green) around the cell bodies of PHF-tau-ir neurons with type II staining (red) in the entorhinal cortex (A–C) and subiculum (D–F) of patients P7 and P1, respectively. Panels (C) and (F) were obtained by combining images (A) and (B), and (D) and (E), respectively. Scale bar: 20 μm.
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Figure 11: (A,B), (D,E), pairs of confocal images from the same section and field to illustrate the presence of GAT-1-ir axon terminals (green) around the cell bodies of PHF-tau-ir neurons with type II staining (red) in the entorhinal cortex (A–C) and subiculum (D–F) of patients P7 and P1, respectively. Panels (C) and (F) were obtained by combining images (A) and (B), and (D) and (E), respectively. Scale bar: 20 μm.

Mentions: The pericellular staining of GAT-1, VGAT, and PV around PHF-tau-ir neurons was similar to that found around PHF-tau-negative cells from both control and AD tissue. For example, we examined the innervation of the soma and proximal dendrites by GAT-1 and VGAT-ir terminals of PHF-tau-ir cells with type I staining in detail (n = 364). Normal innervation was apparent in all the regions studied and the perisomatic innervation was indistinguishable between PHF-tau-ir cells and PHF-tau-negative cells (Figures 10A–F). Remarkably, innervation of the soma and proximal dendrites by GAT-1-ir and VGAT-ir axon terminals was apparently intact even in PHF-tau-ir neurons displaying the type II pattern (n = 382 cells, Figure 11). To quantify these observations, we estimated the number of VGAT-ir boutons around PHF-tau-ir and PHF-tau negative neurons (Figures 10J,K) in two regions (CA1 field and PHG) of patient P7. As shown in Table 4, the number of perisomatic terminals did not differ significantly around PHF-tau-ir and PHF-tau negative neurons.


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)

(A,B), (D,E), pairs of confocal images from the same section and field to illustrate the presence of GAT-1-ir axon terminals (green) around the cell bodies of PHF-tau-ir neurons with type II staining (red) in the entorhinal cortex (A–C) and subiculum (D–F) of patients P7 and P1, respectively. Panels (C) and (F) were obtained by combining images (A) and (B), and (D) and (E), respectively. Scale bar: 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 11: (A,B), (D,E), pairs of confocal images from the same section and field to illustrate the presence of GAT-1-ir axon terminals (green) around the cell bodies of PHF-tau-ir neurons with type II staining (red) in the entorhinal cortex (A–C) and subiculum (D–F) of patients P7 and P1, respectively. Panels (C) and (F) were obtained by combining images (A) and (B), and (D) and (E), respectively. Scale bar: 20 μm.
Mentions: The pericellular staining of GAT-1, VGAT, and PV around PHF-tau-ir neurons was similar to that found around PHF-tau-negative cells from both control and AD tissue. For example, we examined the innervation of the soma and proximal dendrites by GAT-1 and VGAT-ir terminals of PHF-tau-ir cells with type I staining in detail (n = 364). Normal innervation was apparent in all the regions studied and the perisomatic innervation was indistinguishable between PHF-tau-ir cells and PHF-tau-negative cells (Figures 10A–F). Remarkably, innervation of the soma and proximal dendrites by GAT-1-ir and VGAT-ir axon terminals was apparently intact even in PHF-tau-ir neurons displaying the type II pattern (n = 382 cells, Figure 11). To quantify these observations, we estimated the number of VGAT-ir boutons around PHF-tau-ir and PHF-tau negative neurons (Figures 10J,K) in two regions (CA1 field and PHG) of patient P7. As shown in Table 4, the number of perisomatic terminals did not differ significantly around PHF-tau-ir and PHF-tau negative neurons.

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