Improving Neuronal Plasticity in a Mouse Model of FASD

University Of Maryland Baltimore, Baltimore MD

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Abstract

DESCRIPTION (provided by applicant): There is growing evidence that poor neuronal plasticity underlies many of the neurological deficits seen in Fetal Alcohol Spectrum Disorders (FASD). Neuronal plasticity involves making and breaking connections, which in turn are related to potentiation and depression of neuronal responses. These processes are evident in the plasticity of ocular dominance in primary visual cortex. This paradigm is based on functional and morphological cortical changes that occur after a monocular deprivation (MD) by eyelid suture is performed during a critical period of development. Accordingly, in normal animals few days of MD lead to a depression of responses of neurons driven by the deprived (closed) eye, and a potentiation of responses in neurons driven by the experienced (open) eye. Using a ferret model, we demonstrated in the past that early alcohol exposure leads to a permanent impairment in ocular dominance plasticity (ODP). Subsequently, ODP has been used by different groups to study neuronal plasticity in models of Fragile X, Neonatal-Hypoxia ischemia and Angelmann Syndrome. Our studies in ferrets used a combination of optical imaging of intrinsic signals and single unit recordings (in vivo extracellular electrophysiology). Here we wil use a combination of in vivo and in vitro electrophysiology techniques to tease out the mechanisms of early alcohol exposure (EAE) on neuronal plasticity. Specifically we will test the following hypothesis: A) EAE disrupts potentiation BUT NOT depression of responses in cortical layer IV, possibly by affecting glutamatergic neurotransmission. B) EAE disrupts BOTH potentiation and depression of responses in cortical layer II/III possibly by a combined effect on glutamatergic and endocannabinoid neurotransmission. And finally C) That phosphodiesterase type 1 inhibition by vinpocetine and caffeine will restore both potentiation and depression components of neuronal plasticity in alcohol exposed mice. Testing caffeine would be of particular relevance because this drug is routinely used as a therapeutic intervention in premature babies, which could facilitate its translation to FASD subjects.