Seizures are a known co-occurring symptom of
Alzheimer's disease, and they can accelerate cognitive and neuropathological dysfunction. Sub-optimal
vitamin C (
ascorbic acid) deficiency, that is low levels that do not lead the sufferer to present with clinical signs of
scurvy (e.g.
lethargy,
hemorrhage, hyperkeratosis), are easily obtainable with insufficient dietary intake, and may contribute to the oxidative stress environment of both
Alzheimer's disease and
epilepsy. The purpose of this study was to test whether mice that have diminished brain
ascorbic acid in addition to carrying human
Alzheimer's disease mutations in the
amyloid precursor
protein (APP) and
presenilin 1 (PSEN1) genes, had altered electrical activity in the brain (electroencephalography; EEG), and were more susceptible to pharmacologically induced
seizures. Brain
ascorbic acid was decreased in APP/PSEN1 mice by crossing them with
sodium vitamin C transporter 2 (SVCT2) heterozygous knockout mice. These mice have an approximately 30% decrease in brain
ascorbic acid due to lower levels of SVCT2 that supplies the brain with ASC. SVCT2+/-APP/PSEN1 mice had decreased
ascorbic acid and increased oxidative stress in brain, increased mortality, faster seizure onset latency following treatment with
kainic acid (10 mg/kg i.p.), and more ictal events following
pentylenetetrazol (50 mg/kg i.p.) treatment. Furthermore, we report the entirely novel phenomenon that
ascorbic acid deficiency alone increased the severity of
kainic acid- and
pentylenetetrazol-induced
seizures. These data suggest that avoiding
ascorbic acid deficiency may be particularly important in populations at increased risk for
epilepsy and
seizures, such as
Alzheimer's disease.