Basolateral amygdala may hold key to helping prevent drug cravings and relapse

Even if former addicts have ceased using drugs for a lengthy period of time, the craving/desire for those substances remains. Environmental cues that are paired with previous drug use can enhance drug seeking. At the same time, inhibitory cues associated with a drug's unavailability can reduce drug seeking. The amygdala may serve as a critical structure for these interactions.

For this study, alcohol-preferring (P) rats were exposed to the following odors: 1. an odor paired with the operant self-administration of EtOH (CS+); 2. an odor paired with the unavailability of EtOH (CS-); and 3. a neutral odor (CS 0). Subjects were then exposed to on odor for 30 minutes in a non-drug paired environment and neuronal activity was measured through standard c-fos protocols. Microinjections of GABA agonists were then used to pharmacologically silence the bilateral basolateral amygdala (BLA) of P rats in a 2 (active drug or aCSF control injection) by 3 (CS+, CS- or CS 0) experimental design in the operant setting. The results of this study, The Basolateral Amygdala is a Critical Structure for Environment Cue Augmentation of EtOH-Seeking, was presented by Jessica Wilden, MD, 2:55-3:09 p.m., on Monday on, April 16. Co-authors are Sheketha Hauser, PhD; Gerald Deehan Jr., PhD; Zheng-Ming Ding, PhD; William Truitt, PhD; William McBride, MD, PhD; and Zachary Rodd, PhD.

Though neuronal activity was not altered by the conditioned cues in the central or medial amygdala, there was a 60 percent increase in c-fos positive neurons in the basolateral amygdala in CS+ subjects. Since BLA was only activated via the excitatory conditioned cue (CS+), it was hypothesized that activation of BLA enhanced EtOH-seeking. Subsequent pharmacological silencing of the BLA did not affect baseline EtOH-seeking or the inhibitory effect of the CS-, but did prevent enhancement of EtOH-seeking invoked by CS+. Researchers concluded that BLA may mediate the ability of conditioned cues to enhance drug seeking. This region could serve as a target for intervention to reduce drug craving and relapse.