In vivo microdialysis study of brain ethanol concentrations in rats following oral self-administration

Using intracerebral microdialysis, the time-course of ethanol absorption was determined in the striatum of rats after oral self-administration of an ethanol solution. Microdialysis samples were collected every 10 min for 1 hr before and 1 hr after consumption of ethanol over a 5-min period. Substantial levels of ethanol were detected in the brain in the first sample taken after self-administration although these levels did not correlate with the amount of ethanol consumed. Striatal ethanol levels reached maximum or near maximum by the second sample and remained constant for the time points between 20 and 60 min; at these times, brain ethanol levels correlated significantly with the amount consumed. This study demonstrates that oral consumption of ethanol leads to measurable brain levels within a relatively short time. Results suggest that experimental animals may experience the central effects of ethanol during the course of drinking and this could play a role in alcohol preference or avoidance behavior.