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The Phosphodiesterase 10A Inhibitor PF-2545920 Enhances Hippocampal Excitability and Seizure Activity Involving the Upregulation of GluA1 and NR2A in Post-synaptic Densities

View Article: PubMed Central - PubMed

ABSTRACT

Phosphodiesterase regulates the homeostasis of cAMP and cGMP, which increase the strength of excitatory neural circuits and/or decrease inhibitory synaptic plasticity. Abnormally, synchronized synaptic transmission in the brain leads to seizures. A phosphodiesterase 10A (PDE10A) inhibitor PF-2545920 has recently attracted attention as a potential therapy for neurological and psychiatric disorders. We hypothesized that PF-2545920 plays an important role in status epilepticus (SE) and investigated the underlying mechanisms. PDE10A was primarily located in neurons, and PDE10A expression increased significantly in patients with temporal lobe epilepsy. PF-2545920 enhanced the hyperexcitability of pyramidal neurons in rat CA1, as measured by the frequency of action potentials and miniature excitatory post-synaptic current. GluA1 and NR2A expression also increased significantly in post-synaptic densities, with or without SE in rats treated with PF-2545920. The ratio of p-GluA1/GluA1 increased in the presence of PF-2545920 in groups with SE. Our results suggest that PF-2545920 facilitates seizure activity via the intracellular redistribution of GluA1 and NR2A in the hippocampus. The upregulation of p-GluA1 may play an important role in trafficking GluA1 to post-synaptic densities. The data suggest it would be detrimental to use the drug in seizure patients and might cause neuronal hyperexcitability in non-epileptic individuals.

No MeSH data available.


PDE10A expression in the hippocampus and cortex of rats. (A) Triple-label immunofluorescence demonstrated that PDE10A (green) and GFAP (red) were not co-expressed in astrocytes, but PDE10A (green) and MAP2 (blue) were co-expressed in neurons (n = 5). The white squares indicate positive cells in the cortex or hippocampus of rats. Representative Western blot images of hippocampus (B) and cortex (C) of rats at different time points post-status epilepticus. PDE10A increased after SE with a trend, but not significantly (non-SE; 6 h post-SE, PSE-6; 24 h post-SE, PSE-24; 72 h post-SE, PSE-72; n = 5, P > 0.05).
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Figure 1: PDE10A expression in the hippocampus and cortex of rats. (A) Triple-label immunofluorescence demonstrated that PDE10A (green) and GFAP (red) were not co-expressed in astrocytes, but PDE10A (green) and MAP2 (blue) were co-expressed in neurons (n = 5). The white squares indicate positive cells in the cortex or hippocampus of rats. Representative Western blot images of hippocampus (B) and cortex (C) of rats at different time points post-status epilepticus. PDE10A increased after SE with a trend, but not significantly (non-SE; 6 h post-SE, PSE-6; 24 h post-SE, PSE-24; 72 h post-SE, PSE-72; n = 5, P > 0.05).

Mentions: Triple-labeled immunofluorescence staining revealed that PDE10A (green) and MAP2 (blue) were co-expressed in neurons in the hippocampus and cortex of rat models but not with GFAP (red) in astrocytes (Figure 1A). We also examined the levels of PDE10A protein in the hippocampus and cortex of rat models at different time points after SE using Western blotting to confirm PDE10A expression in our animal model. PDE10A expression increased in the hippocampus (Figure 1B, NSE: 0.148 ± 0.025, PSE-6 h: 0.137 ± 0.019, PSE-24 h: 0.217 ± 0.022, PSE-72 h: 0.224 ± 0.061; n = 5, P > 0.05) and cortex (Figure 1C, NSE: 0.174 ± 0.015, PSE-6 h: 0.203 ± 0.015, PSE-24 h: 0.18 ± 0.023, PSE-72 h: 0.198 ± 0.025; n = 5, P > 0.05), but not significantly. The control group was composed of rats that were not successfully kindled (levels < 4) and recorded as the non-SE group.


The Phosphodiesterase 10A Inhibitor PF-2545920 Enhances Hippocampal Excitability and Seizure Activity Involving the Upregulation of GluA1 and NR2A in Post-synaptic Densities
PDE10A expression in the hippocampus and cortex of rats. (A) Triple-label immunofluorescence demonstrated that PDE10A (green) and GFAP (red) were not co-expressed in astrocytes, but PDE10A (green) and MAP2 (blue) were co-expressed in neurons (n = 5). The white squares indicate positive cells in the cortex or hippocampus of rats. Representative Western blot images of hippocampus (B) and cortex (C) of rats at different time points post-status epilepticus. PDE10A increased after SE with a trend, but not significantly (non-SE; 6 h post-SE, PSE-6; 24 h post-SE, PSE-24; 72 h post-SE, PSE-72; n = 5, P > 0.05).
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Related In: Results  -  Collection

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Figure 1: PDE10A expression in the hippocampus and cortex of rats. (A) Triple-label immunofluorescence demonstrated that PDE10A (green) and GFAP (red) were not co-expressed in astrocytes, but PDE10A (green) and MAP2 (blue) were co-expressed in neurons (n = 5). The white squares indicate positive cells in the cortex or hippocampus of rats. Representative Western blot images of hippocampus (B) and cortex (C) of rats at different time points post-status epilepticus. PDE10A increased after SE with a trend, but not significantly (non-SE; 6 h post-SE, PSE-6; 24 h post-SE, PSE-24; 72 h post-SE, PSE-72; n = 5, P > 0.05).
Mentions: Triple-labeled immunofluorescence staining revealed that PDE10A (green) and MAP2 (blue) were co-expressed in neurons in the hippocampus and cortex of rat models but not with GFAP (red) in astrocytes (Figure 1A). We also examined the levels of PDE10A protein in the hippocampus and cortex of rat models at different time points after SE using Western blotting to confirm PDE10A expression in our animal model. PDE10A expression increased in the hippocampus (Figure 1B, NSE: 0.148 ± 0.025, PSE-6 h: 0.137 ± 0.019, PSE-24 h: 0.217 ± 0.022, PSE-72 h: 0.224 ± 0.061; n = 5, P > 0.05) and cortex (Figure 1C, NSE: 0.174 ± 0.015, PSE-6 h: 0.203 ± 0.015, PSE-24 h: 0.18 ± 0.023, PSE-72 h: 0.198 ± 0.025; n = 5, P > 0.05), but not significantly. The control group was composed of rats that were not successfully kindled (levels < 4) and recorded as the non-SE group.

View Article: PubMed Central - PubMed

ABSTRACT

Phosphodiesterase regulates the homeostasis of cAMP and cGMP, which increase the strength of excitatory neural circuits and/or decrease inhibitory synaptic plasticity. Abnormally, synchronized synaptic transmission in the brain leads to seizures. A phosphodiesterase 10A (PDE10A) inhibitor PF-2545920 has recently attracted attention as a potential therapy for neurological and psychiatric disorders. We hypothesized that PF-2545920 plays an important role in status epilepticus (SE) and investigated the underlying mechanisms. PDE10A was primarily located in neurons, and PDE10A expression increased significantly in patients with temporal lobe epilepsy. PF-2545920 enhanced the hyperexcitability of pyramidal neurons in rat CA1, as measured by the frequency of action potentials and miniature excitatory post-synaptic current. GluA1 and NR2A expression also increased significantly in post-synaptic densities, with or without SE in rats treated with PF-2545920. The ratio of p-GluA1/GluA1 increased in the presence of PF-2545920 in groups with SE. Our results suggest that PF-2545920 facilitates seizure activity via the intracellular redistribution of GluA1 and NR2A in the hippocampus. The upregulation of p-GluA1 may play an important role in trafficking GluA1 to post-synaptic densities. The data suggest it would be detrimental to use the drug in seizure patients and might cause neuronal hyperexcitability in non-epileptic individuals.

No MeSH data available.