Abstract

Environmental cues associated with alcohol consumption can trigger craving and facilitate relapse in abstinent alcoholics. We hypothesized that alcohol-seeking behavior evoked by a discrete cue associated with alcohol, would be influenced by context and require glutamate transmission in the basolateral amygdala.

Male, Long-Evans rats that had previously consumed ethanol (EtOH; 15%; v/v) received Pavlovian conditioning sessions in which a 10-sec auditory stimulus (CS; 15 trials per session) was paired with EtOH (0.2 ml/CS). Entries into a fluid port where EtOH was delivered were measured. Pavlovian conditioning occurred in a specific context (alcohol context) and was alternated with sessions in a different context (non-alcohol context) where neither the CS nor EtOH was presented. At test, the CS was presented without EtOH in either the alcohol context or the non-alcohol context. In a separate study, rats received a bilateral microinfusion (0.3 μl/hemisphere) of 0, 0.3, or 1.0 μg of the AMPA glutamate receptor antagonist NBQX [2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione)] in the BLA. The effect of NBQX administration in the CPu on alcohol-seeking behavior elicited by an alcohol-predictive CS was also tested in a non-alcohol context.

Alcohol-seeking elicited by the CS was invigorated in the alcohol context relative to the non-alcohol context. NBQX in the BLA attenuated CS responding at test in both contexts, but had no effect when infused into the CPu.

These data highlight an important role of context in modulating the vigor of Pavlovian-conditioned alcohol-seeking, and suggest that AMPA receptors within the BLA are required for the expression of this behavior.