Abstracts

Rationale: Neonatal seizures can be refractory to treatment and lead to long term epilepsy and cognitive deficits. Using an established neonatal hypoxic seizure (HS) model, we previously showed that seizures activate of the mTORC1 pathway (Talos et al, 2012), as well as enhance in AMPA receptor (AMPAR) expression and function (Rakhade et al., 2008) and later life spontaneous seizures (Rakhade et al.,J Nsci 2011). Importantly, AMPARs activation can regulate the mTORC1 pathway, and the AMPAR antagonist NBQX reverses HS-induced activation of mTORC1 signaling pathway (Lippman-Bell et al., 2013). Given NBQX is not FDA approved for human use, we examined the efficacy of the FDA approved selective AMPAR antagonist Perampanel, a in preventing HS-induced activation of mTORC1 pathway and also subacute increases in seizure susceptibility and long-term spontaneous seizures.Methods: HS were induced by graded global hypoxia in Long Evans rats at postnatal day 10. Perampanel (1mg/kg), NBQX (20mg/kg) or vehicle was administered immediately following HS (every 12h x 4 doses). To measure mTORC1 pathway activation, we analyzed phosphorylated p70-S6 kinase (p-p70S6K) at 1, 3, and 12 hours post-HS by Western blot in hippocampus and cortex. A second-hit kainate (2mg/kg) challenge was performed at 72h post-HS. Spontaneous seizure activity was monitored by 24/7 Video-EEG recordings at P56-80.Results: To measure mTORC1 pathway activation, we analyzed phosphorylated p70S6 kinase (p-p70S6K) at 1, 3, and 12 hours post-HS by Western blot in hippocampus and cortex of rats treated immediately post-HS (every 12 h × 4 doses) with vehicle, Perampanel (1mg/kg), or NBQX (20mg/kg) versus littermate controls receiving the same drug treatments. Perampanel significantly decreased phosphorylation of p70S6 kinase in both hippocampus and cortex at 12 hours post-HS (n=8-10, p<0.01). To test whether Perampanel could reverse HS-induced increases in seizure susceptibility, we performed a second-hit kainate (2mg/kg) challenge at 72hours post-HS. Compared to vehicle treated post-HS rats, the Perampanel treated HS group showed increased latency of KA-induced seizures (hindlimb clonus) (p<0.05). We also tested the efficacy of Perampanel to attenuate long-term spontaneous seizure. 24/7 video-EEG recordings were made from P56-80 post-HS rats and littermate controls. Indeed, Perampanel-treated HS rats had significantly less seizure activity compared to vehicle-treated HS rats (n=5, p<0.001), similar to our previous results with NBQX.Conclusions: Taken together, these results support the therapeutic potential of Perampanel in ameliorating molecular changes of epileptogenic markers and epileptogeneis following neonatal seizures.