The long term goal of this project is to characterize the interaction of ethanol with cellular membranes. Ethanol modifies the properties of the cell membranes of all the major body organs and many of the actions of ethanol are manifest at the level of the cell membrane. The manner by which ethanol, both acutely and chronically, alters the ability of cellular membranes to accommodate and bind exogenous substances such as peptides, proteins and phospholipids will be investigated. The acute and chronic effects of ethanol on the binding properties of rat liver microsomes, mitochondria, brain synaptosomes and their lipid extracts will be characterized. The dependence of lipophile binding on membrane fluidity, curvature stress, and composition will be assessed using nuclear magnetic resonance and electron paramagnetic resonance. It will be established whether the adaptive response to chronic ethanol exposure is an adaptation to chronic membrane fluidization or chronic curvature stress. The acute and chronic effects of ethanol on membrane domain structure in rat liver microsomes and brain synaptosomes, their lipid extracts, and membrane models for the cytoplasmic leaflet of the plasma membrane thought to be involved in the regulation of polyphosphoinositide signaling will be established. The physical and biochemical determinants of domain structure will be assessed using magnetic resonance methods and radiolabel binding methods. The effects of acute and chronic ethanol exposure upon phospholipid (phosphatidylinositol) transfer mediated by the phosphatidylinositol transfer protein will be investigated. Interference with the binding, transfer and incorporation of newly synthesized phosphatidylinositol into inositol lipid signaling pathways in the plasma membrane by acute or chronic ethanol exposure is likely to alter phosphatidylinositol 4,5-bisphosphate dependent processes. The relationship between domain formation and the effects of ethanol on phosphatidylinositol transfer activity will be investigated.
