Role of ventral subiculum in context-induced reinstatement of heroin seeking in rats.

In rats, reexposure to heroin-paired contexts after extinction of lever responding in a different context reinstates heroin seeking. Previous reports indicate that ventral hippocampus/Ca1 region plays a critical role in cocaine-, cue- and context-induced reinstatement of cocaine seeking. Here, we examined whether ventral subiculum, the output region of ventral hippocampus, is involved in context-induced reinstatement of heroin seeking. We found that reversible inactivation of ventral subiculum, but not posterior Ca1, with the gamma-aminobutyric acid agonists muscimol + baclofen decreased context-induced reinstatement of heroin seeking. Our findings, together with previous studies on cocaine seeking, indicate a critical role of ventral subiculum in context-induced relapse across drug classes.