Morris and colleagues had previously used PET to show that acute inflammation in healthy subjects caused amplification of dopamine release in response to a stimulant (methylphenidate). The new work, by Drs. Hoye and Zakiniaeiz, extends the finding to an addicted population and is a critical piece of a larger, NIDA-funded, investigation to link inflammation and stress to amplification of dopamine release and ultimately to relapse to drug-seeking. There has been an increasing interest in recent years in identifying environmental causes of drug-taking.
The second figure shows dopamine release in the striatum under placebo (left) and under endotoxin (right), a derivative of bacterial cell membranes administered to volunteers to simulate conditions of mild acute stress.