Since the genetic risk for alcoholism in humans must be based on the genetic differences in physiological reactions to ethanol, these studies may help in pointing out what those effects are. Independent of this however, the use of animal genetics to study the mechanism of action of ethanol is an important tool in the armamentarium of methods to develop better treatment and prevention measures for humans. This project proposes to continue the selective breeding program to develop rats with a high (HAS) or low (LAS) initial (ie. first dose) sensitivity of the central nervous system to alcohol. The animals have proven useful in elucidating the mechanism by which alcohol depresses the central nervous system. The project has replicated the classic selection for initial central nervous system sensitivity to alcohol in mice, the short- and long- sleep mice (55 and LS) with a much more closely controlled genetic protocol, including replicate and control lines. Currently the lines are still segregating, especially in the direction of the HAS lines. The current results point to a marked difference between the 55 and LS mice in that the rats are differentially sensitive to barbiturates, whereas the LS and 55 mice are not. The rats are also differentially sensitive to halothane, where the mice are not. Since it is thought that these agents act on the major neuronal inhibitory system in the brain, the GABA system, it may be that we have selected a different GABA subunit receptor in the rats than is present in the mice. At a molecular genetic level, this may prove to be helpful in dissecting the effects of ethanol on this system. The rats develop acute tolerance to ethanol. This can be demonstrated behaviorally following a single hypnotic dose of ethanol. We have also demonstrated that the cerebellar Purkinje cells in the behaviorally resistant rats are also resistant to the effects of ethanol on cell firing rates. Experiments to correlate these two findings are planned. The possible role of neurotensin in the acute and chronic effects of ethanol has been investigated. Generally the results replicate that found in the mice. The possible role of neurotensin in tolerance and dependence is planned in the next grant period. GRANT=R01AG10886 The proposal addresses the thesis that chronic inflammatory diseases - common in an ageing population - accelerates the development of atherosclerosis. During the acute phase response, serum amyloid A protein (A-SAA), an apolipoprotein, increases 1,000 fold and becomes a major component of high density lipoprotein (HDL). In spite of intense modern interest in the HDL particle, the teleological role of this alteration of HDL apolipoprotein composition during inflammation is unknown. We propose that A-SAA mediate the remodelling of HDL to accommodate a modified physiological requirement for this particle during inflammation namely phospholipid delivery to sites of inflammation. Chronic persistence of A- SAA render HDL less capable of mediating reverse cholesterol transport and to protect low density lipoprotein against oxidative modification providing an explanation for the increased mortality of patients with chronic inflammatory disease from cardiovascular disease. In addition to the acute phase A-SAA subfamily, we have identified new apolipoprotein molecules in man (C-SAA) and mouse (SAA5) as members of what now constitutes a SAA family. These form a distinct subfamily differing from A-SAA in structure and the fact that they are constitutive on normal HDL where they represent more than 95% of total SAA on this particle. We propose that these play a role in the function of this particle in the healthy state by promoting lipid exchange between lipoprotein particles. Given the centrality of HDL in lipoprotein metabolism and its dynamic interaction with other lipoproteins, experiments in the animal model is essential to complement more mechanistic studies. We propose to use transgenic mice that we have generated to study the interplay between the two sub families of the SAA superfamily and how they influence HDL impacting on other lipoproteins and whether there presence on HDL promotes atherosclerosis.
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