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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

Miniature excitatory post-synaptic currents (mEPSCs) recorded from granule cells born after status epilepticus (SE) and sham treatment (Control). The retroviral CAG-GFP vector was injected into the dentate gyrus 5 days after induction of SE or saline injection and cells were recorded at least 70 days after retroviral vector injection. (A) Fluorescent (GFP) and differential interference contrast (DIC) images illustrate the recorded cells. (B) Representative traces of mIPSCs recorded at -70 mV at room temperature in the presence of 1 μM tetrodotoxin- and 30 μM bicuculline. (C) Quantitative comparisons of frequency, amplitude, 10–90% rise time, decay time, area, and interval time of mEPSCs events. Statistical comparisons between the control (n = 6) and SE (n = 6) groups were made by unpaired t-test.
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Figure 6: Miniature excitatory post-synaptic currents (mEPSCs) recorded from granule cells born after status epilepticus (SE) and sham treatment (Control). The retroviral CAG-GFP vector was injected into the dentate gyrus 5 days after induction of SE or saline injection and cells were recorded at least 70 days after retroviral vector injection. (A) Fluorescent (GFP) and differential interference contrast (DIC) images illustrate the recorded cells. (B) Representative traces of mIPSCs recorded at -70 mV at room temperature in the presence of 1 μM tetrodotoxin- and 30 μM bicuculline. (C) Quantitative comparisons of frequency, amplitude, 10–90% rise time, decay time, area, and interval time of mEPSCs events. Statistical comparisons between the control (n = 6) and SE (n = 6) groups were made by unpaired t-test.

Mentions: By holding cells at −70 mV, both mIPSCs and mEPSCs were recorded at room temperature. As shown in Figure 5, it appeared that mIPSCs recorded from newborn granule cells in the SE group were similar to those in the control group; statistical analyses revealed that neither frequency, amplitude, 10–90% rise time, decay time, area, nor interval time were significantly different between the control (n = 6) and SE (n = 6) groups. For mEPSCs (Figure 6), the amplitude in the SE group (n = 6) was significantly smaller than that in the control group (n = 6). In addition, there was a trend toward lower event frequency in the SE group (p = 0.153, control vs. SE).


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)

Miniature excitatory post-synaptic currents (mEPSCs) recorded from granule cells born after status epilepticus (SE) and sham treatment (Control). The retroviral CAG-GFP vector was injected into the dentate gyrus 5 days after induction of SE or saline injection and cells were recorded at least 70 days after retroviral vector injection. (A) Fluorescent (GFP) and differential interference contrast (DIC) images illustrate the recorded cells. (B) Representative traces of mIPSCs recorded at -70 mV at room temperature in the presence of 1 μM tetrodotoxin- and 30 μM bicuculline. (C) Quantitative comparisons of frequency, amplitude, 10–90% rise time, decay time, area, and interval time of mEPSCs events. Statistical comparisons between the control (n = 6) and SE (n = 6) groups were made by unpaired t-test.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 6: Miniature excitatory post-synaptic currents (mEPSCs) recorded from granule cells born after status epilepticus (SE) and sham treatment (Control). The retroviral CAG-GFP vector was injected into the dentate gyrus 5 days after induction of SE or saline injection and cells were recorded at least 70 days after retroviral vector injection. (A) Fluorescent (GFP) and differential interference contrast (DIC) images illustrate the recorded cells. (B) Representative traces of mIPSCs recorded at -70 mV at room temperature in the presence of 1 μM tetrodotoxin- and 30 μM bicuculline. (C) Quantitative comparisons of frequency, amplitude, 10–90% rise time, decay time, area, and interval time of mEPSCs events. Statistical comparisons between the control (n = 6) and SE (n = 6) groups were made by unpaired t-test.
Mentions: By holding cells at −70 mV, both mIPSCs and mEPSCs were recorded at room temperature. As shown in Figure 5, it appeared that mIPSCs recorded from newborn granule cells in the SE group were similar to those in the control group; statistical analyses revealed that neither frequency, amplitude, 10–90% rise time, decay time, area, nor interval time were significantly different between the control (n = 6) and SE (n = 6) groups. For mEPSCs (Figure 6), the amplitude in the SE group (n = 6) was significantly smaller than that in the control group (n = 6). In addition, there was a trend toward lower event frequency in the SE group (p = 0.153, control vs. SE).

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