engleski

Structural plasticity in the hippocampal dentate gyrus

The dentate gyrus (DG) is a three-dimensionally curved structure composed of a compact layer containing densely packed granule cells. One of the more remarkable characteristics of the DG is its plasticity. In addition to the phenomenon of adult granule cell neurogenesis, other plastic changes are observed at granule cell synapses, such as LTP, LTD, or the formation of new synaptic contacts. Due to its relatively simple cytoarchitecture and the laminated termination of afferent fiber systems the DG has been frequently used as a model system to analyze normal as well as pathological processes of the brain. One of the classical model system used to study lesion-induced plasticity is the reorganization of the DG following entorhinal cortex lesion. Although this experimental model has been extensively characterized in the rat, data on the reorganization in the denervated mouse DG are scarce. Since this limits the use of genetic tools, we have analyzed the dendritic reorganization of denervated granule cells in Thy-1 GFP transgenic mouse. Single GFP-labeled granule cells were 3D-reconstructed in their entirety using confocal microscopy and Neurolucida software at different time points upon denervation. Entorhinal denervation results in protracted and long-term structural alterations of mouse granule cells. These changes occur in spite of collateral sprouting of surviving afferent fibers, suggesting that the spontaneously occurring reinnervation of granule cells is insufficient to maintain the granule cell arbor. Our study provides a useful morphological baseline for further studies on dendritic denervation processes in vivo, in particular for studies using different mouse mutants.

Plasticity; Dentate gyrus; Entorhinal cortex lesion; Denervation; Regeneration

nije evidentirano