Measuring Behavior 2005: LaBounty

A system for administering and measuring responses to ethanol in rats

L.P. LaBounty, E.P. Wiertelak and G.A. Cousens

Department of Psychology and Neuroscience Studies Program, Macalester College, Saint Paul, MN, USA

Here we describe efforts to develop a new method to permit examination of the effects of acute ethanol exposure and ethanol withdrawal on CO2 sensitivity in rats. In human Subjects, acute ethanol intoxication is associated with reduced respiratory responses to CO2 challenge, and withdrawal from chronic ethanol exposure is associated with enhanced respiratory responses to CO2 challenge. CO2 sensitivity is considered to be a strong indicator offior predictor of anxiety in humans. In this procedure, ethanol dependence is induced in rats by chronic (20 days) and continuous exposure to increasing concentrations of ethanol vapor produced by passing chamber air over ethanol dripped into a heated Erlenmeyer flask. CO2 sensitivity is determined by brief challenge with CO2 ranging in concentration between 2.5 and 10% using custom-built barometric chambers coupled to an analog pressure transducer. Voltage changes are digitized and passed to a physiological recording system (Plexon Recorder) for analysis. It is predicted that reduced sensitivity to CO2 will be observed relative to control Subjects immediately after ethanol exposure and that sensitivity will elevate relative to control Subjects as behavioral measures of ethanol withdrawal emerge. Consistent with the notion that CO2 hypersensitivity is a consequence of enduring ethanol-induced pathophysiology in respiratory regulation, it is further predicted that hypersensitivity will outlast behavioral measures of ethanol withdrawal. Preliminary studies have been completed and further data collection is currently underway. Ultimately, we expect to determine whether CO2 sensitivity can serve as an acute measure of anxiety in the development of an animal analogue for the study of ethanol-anxiety relationships.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.