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Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat.

Gao F, Song X, Zhu D, Wang X, Hao A, Nadler JV, Zhan RZ - Front Cell Neurosci (2015)

Bottom Line: The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling.After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells.Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Shandong University School of Medicine Jinan, China.

ABSTRACT
To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.

No MeSH data available.


Related in: MedlinePlus

A comparison of dendritic spine density in mature granule cells born after status epilepticus (SE) or sham treatment (Control). Z-series stacks were conducted in dendritic segments that were located in the middle molecular layer (middle ML) and outer molecular layer (Outer ML). (A) Representative confocal images of dendritic segments in the middle ML and outer ML in a control rat. (B) Representative confocal images of dendritic segments in the middle ML and outer ML in an SE rat. (C) Bar graphs comparing total and mushroom-like spine densities between the control and SE rats (n = 6 animals each). For each animal, spine densities were calculated from three cells; total six dendritic segments (three in the middle molecular layer and another three in the outer molecular layer) each cell were scanned and all values in the same layer were averaged. The left two panels represent dendritic segments in the middle molecular layer, and the two panels in the right represent dendritic segments in the outer molecular layer.
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Figure 3: A comparison of dendritic spine density in mature granule cells born after status epilepticus (SE) or sham treatment (Control). Z-series stacks were conducted in dendritic segments that were located in the middle molecular layer (middle ML) and outer molecular layer (Outer ML). (A) Representative confocal images of dendritic segments in the middle ML and outer ML in a control rat. (B) Representative confocal images of dendritic segments in the middle ML and outer ML in an SE rat. (C) Bar graphs comparing total and mushroom-like spine densities between the control and SE rats (n = 6 animals each). For each animal, spine densities were calculated from three cells; total six dendritic segments (three in the middle molecular layer and another three in the outer molecular layer) each cell were scanned and all values in the same layer were averaged. The left two panels represent dendritic segments in the middle molecular layer, and the two panels in the right represent dendritic segments in the outer molecular layer.

Mentions: Z-series stacks were made in dendritic segments that were located in the middle and outer molecular layers and dendritic spines were counted on constructed 3D-images. Representative images and statistical comparisons are shown in Figure 3. Both mushroom-like and non-mushroom-like spines can be readily identified (Figures 3A,B). In the control rats, total spine densities in dendritic segments of the middle molecular and outer molecular layers were 2.15 ± 0.11 and 2.42 ± 0.09 spines/μm (n = 6), respectively. For the dendritic segments located in the middle molecular layer, both total and mushroom-like spine densities were not statistically different between the controls (n = 6) and SEs (n = 6) (Figure 3C, left two panels). However, mushroom-like spine density in the dendritic segments located in the outer molecular layer in SE rats (n = 6) was significantly denser than that in the control rats (n = 6), as shown in the right panel of Figure 3C.


Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat.

Gao F, Song X, Zhu D, Wang X, Hao A, Nadler JV, Zhan RZ - Front Cell Neurosci (2015)

A comparison of dendritic spine density in mature granule cells born after status epilepticus (SE) or sham treatment (Control). Z-series stacks were conducted in dendritic segments that were located in the middle molecular layer (middle ML) and outer molecular layer (Outer ML). (A) Representative confocal images of dendritic segments in the middle ML and outer ML in a control rat. (B) Representative confocal images of dendritic segments in the middle ML and outer ML in an SE rat. (C) Bar graphs comparing total and mushroom-like spine densities between the control and SE rats (n = 6 animals each). For each animal, spine densities were calculated from three cells; total six dendritic segments (three in the middle molecular layer and another three in the outer molecular layer) each cell were scanned and all values in the same layer were averaged. The left two panels represent dendritic segments in the middle molecular layer, and the two panels in the right represent dendritic segments in the outer molecular layer.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4596052&req=5

Figure 3: A comparison of dendritic spine density in mature granule cells born after status epilepticus (SE) or sham treatment (Control). Z-series stacks were conducted in dendritic segments that were located in the middle molecular layer (middle ML) and outer molecular layer (Outer ML). (A) Representative confocal images of dendritic segments in the middle ML and outer ML in a control rat. (B) Representative confocal images of dendritic segments in the middle ML and outer ML in an SE rat. (C) Bar graphs comparing total and mushroom-like spine densities between the control and SE rats (n = 6 animals each). For each animal, spine densities were calculated from three cells; total six dendritic segments (three in the middle molecular layer and another three in the outer molecular layer) each cell were scanned and all values in the same layer were averaged. The left two panels represent dendritic segments in the middle molecular layer, and the two panels in the right represent dendritic segments in the outer molecular layer.
Mentions: Z-series stacks were made in dendritic segments that were located in the middle and outer molecular layers and dendritic spines were counted on constructed 3D-images. Representative images and statistical comparisons are shown in Figure 3. Both mushroom-like and non-mushroom-like spines can be readily identified (Figures 3A,B). In the control rats, total spine densities in dendritic segments of the middle molecular and outer molecular layers were 2.15 ± 0.11 and 2.42 ± 0.09 spines/μm (n = 6), respectively. For the dendritic segments located in the middle molecular layer, both total and mushroom-like spine densities were not statistically different between the controls (n = 6) and SEs (n = 6) (Figure 3C, left two panels). However, mushroom-like spine density in the dendritic segments located in the outer molecular layer in SE rats (n = 6) was significantly denser than that in the control rats (n = 6), as shown in the right panel of Figure 3C.

Bottom Line: The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling.After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells.Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Shandong University School of Medicine Jinan, China.

ABSTRACT
To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.

No MeSH data available.


Related in: MedlinePlus