L-GLUTAMATE ABOLISHES DIFFERENTIAL RESPONSES TO ALCOHOL DEPRIVATION IN MICE

Hybrid mice produced by crossing CBA and C57BL lines were deprived of alcohol for three days after prolonged prior access. Subsequently, whe n access was first given to a flavored 30% alcohol solution, about hal f of the mice showed a greatly elevated rate of drinking during the fi rst 1.5 h, characteristic of the alcohol-deprivation effect (ADE), but other mice showed no increase. Repeating the test three weeks later s howed that having or lacking an ADE is a stable group characteristic. Behavioral differences were found on cross-maze and slip funnel tests between mice that had an ADE and those that lacked it. Topical applica tion of L-glutamate to the frontal cortex prevented the subsequent ele vation of alcohol drinking during the first 1.5 h after deprivation bu t did not alter drinking during the remaining 22.5 h. L-glutamate trea tment also affected those cross-maze behaviors found to be related to the ADE. The results suggest that frontal cortex neurons sensitive to L-glutamate are necessary for the ADE and that comparisons between hyb rid mice having and lacking an ADE might be used for determining the n euronal mechanisms responsible for the effect.