Excessive alcohol consumption is a prerequisite for the development of alcohol dependence. In order to understand the mechanisms of alcoholism progression, which mediate the switch from controlled alcohol consumption to alcohol abuse and alcohol dependence, it is important to identify molecular targets affected by high alcohol intake in individual neuronal populations of the reward circuit. The main goal of this proposal is two-fold: 1) to determine the effects of high alcohol consumption on gene expression and cellular physiology in the nucleus accumbens (NA) neurons projecting to ventral tegmental area (VTA) and 2) to establish a methodology for labeling and profiling multiple neuronal populations in the reward circuit. We will use alcohol- preferring C57BL6 x FVB F1 hybrid mice that will drink intoxicating amounts of alcohol in a binge fashion for several days. Two populations of accumbal GABA-ergic medium spiny neurons, one projecting to VTA and the other projecting to the ventral pallidum will be labeled by injecting a retrograde tracer, cholera toxin subunit B conjugated to an Alexa Fluor, into the respective projection target areas. Part of the labeled NA neurons will be collected using laser capture microdissection and gene expression will be measured using microarrays and RNA sequencing. The other part will be used for electrophysiological recordings. A gene network approach will be used to identify individual genes and molecular pathways correlated with neuronal physiology and alcohol intake. This study will identify cell type - specific alcohol- sensitive molecular targets that may eventually b used to reduce alcohol intake via circuit- specific manipulation of neuronal activity. The long-term goal of this research is to determine molecular mechanisms of cellular adaptation to alcohol in individual neuronal populations of the neurocircuits that mediate alcohol actions. This knowledge may be used to develop new drugs for the prevention and treatment of alcoholism.
Understanding the role of individual neuronal populations is crucial to understanding behavior and disease. The current proposal aims to identify cell type - specific alcohol-sensitive molecular targets that may be used to reduce alcohol intake via circuit-specific manipulation of neuronal activity. The ultimate goal of this line of research is to promot the development of new therapies for human alcoholism.
