Entorhinal axons exhibit sprouting in CA1 subfield of the adult hippocampus in a rat model of temporal lobe epilepsy

@article{Shetty2002EntorhinalAE,
  title={Entorhinal axons exhibit sprouting in CA1 subfield of the adult hippocampus in a rat model of temporal lobe epilepsy},
  author={Ashok K. Shetty},
  journal={Hippocampus},
  year={2002},
  volume={12}
}
Intracerebroventricular kainic acid administration in rat, a model of temporal lobe epilepsy, results in CA3 pyramidal neuron degeneration leading to deafferentation of CA1 pyramidal neurons. Denervation in CA1 shows a near‐complete recovery of synaptic density over 2–3 months, but the source of axons participating in the reinnervation is not clear. This study investigated the contribution of the entorhinal cortex in this reinnervation by comparing the distribution of the entorhinal axons in… 
Restoration of calbindin after fetal hippocampal CA3 cell grafting into the injured hippocampus in a rat model of temporal lobe epilepsy
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Specific cell grafting restores the injury‐induced loss of calbindin in the adult hippocampus, likely via restitution of the disrupted circuitry, due to disruption of the hippocampal circuitry leading to hyperexcitability.
Hippocampal neurotrophin levels in a kainate model of temporal lobe epilepsy: a lack of correlation between brain‐derived neurotrophic factor content and progression of aberrant dentate mossy fiber sprouting
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Results suggest that the period of robust mossy fiber sprouting does not correlate with the phase of post‐lesion BDNF upregulation, and shows a relationship with the time of upregulation of neurotrophins NGF and NT‐3.
Nestin expression in hippocampal astrocytes after injury depends on the age of the hippocampus
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It is hypothesized that the capability of astrocytes for re‐expressing nestin in response to CNS injury diminishes as a function of age, and nestin‐immunoreactive radial glia framework after lesion is not impaired with aging in the ependymal lining of the CA3 region.
Recovery of afferent function and synaptic strength in hippocampal CA1 following traumatic brain injury.
TLDR
These results are in agreement with anatomical evidence showing a profound deafferentation, followed by a remarkable re-enervation, of ipsilateral CA1 in the first few weeks after traumatic brain injury.
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TLDR
Anterograde tracing experiments demonstrated that all regions of the entorhinal cortex project to the outer two‐thirds of the molecular layer of the dentate gyrus and to much of the radial extent of the stratum lacunosum‐moleculare of CA3 and CA2.
Fetal Hippocampal Grafts Containing CA3 Cells Restore Host Hippocampal Glutamate Decarboxylase-Positive Interneuron Numbers in a Rat Model of Temporal Lobe Epilepsy
TLDR
It is hypothesized that enduring loss of GAD expression in hippocampal interneurons after intracerebroventricular KA is attributable to degeneration of their CA3 afferent input, and fetal CA3 grafts can restore GAD interneuron numbers through graft axon reinnervation of the host.
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TLDR
The results suggest that there is no special barrier to the growth of entorhinal fibers and that the inner part of molecular layer of the dentate gyrus is capable of receiving afferents other than those normally present.
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TLDR
Results indicate that, following kainate lesions, there is sprouting of local axon collaterals of CA1 pyramidal cells in stratum oriens and in the alveus, which may contribute to the epileptiform activity in the CA1 area by providing recurrent excitation via newly formed synaptic, and perhaps even autaptic, contacts with pyramsidal cell dendrites.
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TLDR
These findings provide morphological evidence for lamina-specific sprouting of an inhibitory commissural projection that normally terminates in the outer molecular layer that suggests that inhibitory fibers participate in the replacement of the excitatory perforant pathway after entorhinal lesion.
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TLDR
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TLDR
The results of the present study indicate that rostrocaudally oriented zones of cells that cut across several cytoarchitectonic subdivisions of the entorhinal cortex give rise to topographically organized projections to the dentate gyrus.
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