Angelman syndrome (AS) is a genetic neurodevelopmental disorder, most commonly caused by deletion or mutation of the maternal allele of the UBE3A gene, with behavioral phenotypes and seizures as key features. Currently no treatment is available, and therapeutics are often ineffective in controlling AS-associated seizures. Previous publications using the Ube3a maternal deletion model have shown behavioral and seizure susceptibility phenotypes, however findings have been variable and merit characterization of electroencephalographic (EEG) activity. In this study, we extend previous studies comparing the effect of genetic background on the AS phenotype by investigating the behavioral profile, EEG activity, and seizure threshold. AS C57BL/6J mice displayed robust behavioral impairments, spontaneous EEG polyspikes, and increased cortical and hippocampal power primarily driven by delta and theta frequencies. AS 129 mice performed poorly on wire hang and contextual fear conditioning and exhibited a lower seizure threshold and altered spectral power. AS F1 hybrid mice (C57BL/6J × 129) showed milder behavioral impairments, infrequent EEG polyspikes, and fewer spectral power alterations. These findings indicate the effect of common genetic backgrounds on the Ube3a maternal deletion behavioral, EEG, and seizure threshold phenotypes. Our results will inform future studies on the optimal strain for evaluating therapeutics with different AS-like phenotypes.

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Extracelluar signal‐regulated kinase (ERK) pathway activation has been demonstrated following convulsant stimulation; however, little is known about the molecular targets of ERK in seizure models. Recently, it has been shown that ERK phosphorylates Kv4.2 channels leading to down‐regulation of channel function, and substantially alters dendritic excitability. In the kainate model of status epilepticus (SE), we investigated whether ERK phosphorylates Kv4.2 and whether the changes in Kv4.2 were evident at a synaptosomal level during SE. Western blotting was performed on rat hippocampal whole cell, membrane, synaptosomal, and surface biotinylated extracts following systemic kainate using an antibody generated against the Kv4.2 ERK sites and for Kv4.2, ERK, and phospho‐ERK. ERK activation was associated with an increase in Kv4.2 phosphorylation during behavioral SE. During SE, ERK activation and Kv4.2 phosphorylation were evident at the whole cell and synaptosomal levels. In addition, while whole‐cell preparations revealed no alterations in total Kv4.2 levels, a decrease in synaptosomal and surface expression of Kv4.2 was evident after prolonged SE. These results demonstrate ERK pathway coupling to Kv4.2 phosphorylation. The finding of decreased Kv4.2 levels in hippocampal synaptosomes and surface membranes suggest additional mechanisms for decreasing the dendritic A‐current, which could lead to altered intrinsic membrane excitability during SE.