The present line of inquiry will focus exclusively on the role of NMDA receptors (NMDARs) in triggering electrographic ethanol withdrawal seizures, a prime cause of morbidity and mortality in chronic ethanol abusers. Electrophysiological and microfluorometric monitoring will be employed in the service of a rigorous examination of the changes in NMDAR-mediated neurotransmission caused by chronic ethanol exposure and withdrawal, and the temporal relationship between these changes and the onset of ethanol withdrawal hyperexcitability. Using the hippocampal blind slice patch-clamp preparation, recordings of NMDAR-mediated miniature synaptic events will be made from hippocampal explants in the setting of chronic ethanol administration, and at incremental time-points after withdrawal of ethanol. Frequency and amplitude analysis of these events will be employed to determine a pre- or postsynaptic focus of withdrawal-induced electrophysiological changes. Withdrawal-induced changes in NMDAR-mediated miniature events will be temporally correlated with the onset of epileptiform discharge patterns detected via long-term field potential monitoring. Confocal imaging of GFP-tagged NMDARs expressed by explanted hippocampal neurons, using multiphoton excitation to enhance resolution and limit photo-oxidation, will be employed to directly visualize withdrawal-induced changes in NMDAR trafficking.
