According to research presented recently at the 80th Annual Scientific Meeting of the American Association of Neurological Surgeons (AANS) in Miami, researchers have discovered evidence that the basolateral amygdala may play a critical role in helping to adjust the ability of conditioned hints or triggers that enhance a recovering addict's craving or drug seeking.

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.