Epilepsy is among the most common neurological diseases worldwide. Over 30 anti-seizure medications (ASMs) are available to treat seizures; however, one-third of people with epilepsy are resistant to their treatment options. The mechanisms behind these pharmacoresistant seizures are not fully understood, but experimental models like the 6Hz or MES mouse seizure models are useful for investigating contributing factors. Recent findings from our lab demonstrate that different brain regions are activated in response to distinct seizure-types, but treatment with ASMs does not alter this activation, regardless of ASM efficacy. Our previous studies used cFOS as a marker of neuronal activity, but since this is not specific to the type of neuron activated, this project focused on calbindin (CALB), a calcium binding protein commonly found in interneurons. We hypothesize that the cFOS immunoreactivity seen in mice who were protected from seizures would be a result of the activation of inhibitory neurons as indicated by increased colocalization between cFOS and CALB-positive neurons. Adult male CF-1 mice were treated with 3 mechanistically different ASMs: cenobamate, levetiracetam, and phenytoin, before being challenged with a focal (6Hz) or generalized (MES) seizure at the time of peak pharmacological effect. Brains were collected 90 minutes after each stimulation and processed for immunohistochemical labeling of DAPI, cFOS, and CALB. Preliminary data suggests that the number of activated CALB cells (e.g., cFOS+CALB cells) did not differ between protected or unprotected mice across brain regions or following certain seizure types. This indicates that the activation of inhibitory neurons might not be a major factor in seizure protection. However, further testing is needed to identify and quantify all inhibitory neuron subtypes to better understand the mechanisms contributing to pharmacoresistant seizures. 

Epilepsy is a brain disorder characterized by spontaneous seizures. Many people with epilepsy treat their seizures with antiseizure medicines (ASMs), which must be taken daily, even through major life milestones such as pregnancy. However, there is little evidence on how these medicines, particularly when taken together, influence long-term brain development in children born to mothers taking ASM therapy. Understanding these consequences is crucial, especially for newer ASMs and drug-resistant epilepsy patients that require multiple medications. Therefore, this experimental study investigated how epilepsy therapy impacts birth and developmental outcomes in rodent offspring born to mothers taking multiple ASMs.
Timed-pregnant female rats were orally administered one of the four epilepsy treatments at therapeutically relevant doses during gestation and lactation. Treatments included: placebo, lamotrigine, levetiracetam, or combined lamotrigine and levetiracetam. General characteristics of birth outcomes were monitored, including gestational length, offspring growth rate, and major developmental milestones. No differences were detected in gestational length for our first cohort (22–23 days). Maternal weight gain varied between 78g to 115g, or 30–39% of their baseline weight. No significant differences were detected in litter size (9–15 pups), date of fur development (postnatal day 10, PND 10), or the average date of eye opening (PND 14), with some pups ranging from PND 13 to PND 15. The average mass for offspring was inversely correlated with litter size, but not treatment. These preliminary findings are inconclusive about the impact of ASMs on early developmental outcomes in offspring. Future studies will replicate each cohort and evaluate the long–term cognitive and behavioral effects. Grasping these impacts can guide safer therapeutic approaches for epilepsy patients during pregnancy.