The P2X7 receptor in activated microglia promotes depression- and anxiety-like behaviors in lithium -pilocarpine induced epileptic rats.

Depressive and anxious behaviors are the most common psychiatric symptoms of epilepsy, and may aggravate the epileptic condition and affect the patient's quality of life. Accumulating data obtained from both experimental animal models and patients have convincingly shown a critical role of P2X7 receptor (P2X7R) during depression and anxiety. Our study showed for the first time that the P2X7R is involved in promoting depression- and anxiety-like behaviors in lithium pilocarpine-induced epileptic rats. More importantly, direct anti-depressive and anti-anxiety effects were produced by the P2X7R antagonist Brilliant Blue G (BBG) is in this study, and the effect was similar to that of the classic anti-depressant and anti-anxiety drug fluoxetine. We also found that BBG did not affect the development of spontaneous recurrent seizures (SRS) and had a neuroprotective effect via inhibition of microglial activation after status epilepticus (SE). Thus, our data provide evidence that the P2X7R in activated microglia promotes depression- and anxiety-like behaviors in lithium-pilocarpine induced epileptic rats. Since previous studies have indicated that some anti-depression and anti-anxiety drugs may exacerbate seizures, our data support that the P2X7R is a promising therapeutic target for epilepsy associated with depression and anxiety.

Losartan inhibits development of spontaneous recurrent seizures by preventing astrocyte activation and attenuating blood-brain barrier permeability following pilocarpine-induced status epilepticus.

Blood-brain barrier (BBB) damage and astrocyte activation are important cause of recurrent epilepsy. There is experimental evidence for increased angiotensin receptor type 1 (AT1) expression during BBB breakdown and brain injury, and that blocking the AT1 receptor (e.g., with losartan) can improve microcirculation, attenuate inflammation and oxidative stress, and exhibit neuroprotective effects. Thus, in the present study, we examined the effects of losartan on status epilepticus-induced astrocyte activation and BBB damage in the lithium-pilocarpine model of epilepsy in rats. We found that losartan treatment reduced astrocyte activation and BBB damage. However, under physiological condition, losartan have not effect on BBB permeability and astrocyte activation. Further, losartan exhibited a direct antiepileptic effect, which was mediated, at least in part by normalizing AQP4 expression after SE. As the changes of AQP4 expression were closely related to astrocyte activation and BBB permeability, the antiepileptic action of losartan likely relates to its effects on astrocyte activation and BBB permeability. Overall, these data suggest that losartan may be a useful antiepileptic agent in the clinic, either alone or in combination with other antiepileptic drugs.

The PPARγ agonist rosiglitazone prevents neuronal loss and attenuates development of spontaneous recurrent seizures through BDNF/TrkB signaling following pilocarpine-induced status epilepticus.

Hippocampal neuronal loss plays an important role in epileptogenesis, and it is considered a trigger of repeated spontaneous recurrent seizures (SRS). The BDNF/TrkB signaling pathway regulates neuronal plasticity in the CNS, and promotes epileptogenesis. Previous studies have shown that Peroxisome proliferator-activated receptor gamma (PPARγ) agonists exert neuroprotective effects by inhibiting oxidative stress and inflammation in epilepsy. In the present study, the PPARγ agonist rosiglitazone inhibited increases in BDNF and TrkB after status epilepticus (SE), and also prevented hippocampal neuronal loss. More importantly, our study showed that rosiglitazone suppressed SRS. However, the effects of rosiglitazone were significantly reversed by cotreatment with K252a, an antagonist of TrkB. Additionally, rosiglitazone did not affect the development and severity of SE. Thus, our data provide evidence that rosiglitazone exerts neuroprotective and antiepileptic effects involve BDNF/TrkB signaling. Our study also offers new perspectives for the treatment of epilepsy.

The PPARγ agonist rosiglitazone prevents cognitive impairment by inhibiting astrocyte activation and oxidative stress following pilocarpine-induced status epilepticus.

Epilepsy is commonly associated with cognitive impairment. Astrocyte activation and oxidative stress occur following seizures, and play a role in the pathological injury of epilepsy with cognitive impairment. The peroxisome proliferator-activated receptor gamma (PPARγ) has been shown to exhibit neuroprotective and antioxidative effects in CNS diseases. Thus, we hypothesized that rosiglitazone, a PPARγ agonist, would prevent cognitive impairment by inhibiting astrocyte activation and regulating glutathione (GSH) homeostasis after status epilepticus (SE). Using a lithium pilocarpine-induced SE model, we found that rosiglitazone significantly prevented cognitive impairment induced by SE, and potently inhibited astrocyte activation with maintenance of GSH homeostasis in the hippocampus after SE. These protective effects were significantly reversed by co-treatment with the PPARγ antagonist T0070907. These data suggest that rosiglitazone can improve cognitive impairment, and inhibit astrocyte activation and oxidative damage following SE. Rosiglitazone may be a promising agent for treatment of epilepsy involving SE-induced cognitive impairment.