News and Views

Nature Neuroscience 10, 9 - 10 (2007)

Tolerance to opiate reward: role of midbrain IRS2-Akt pathway

Brandon K Harvey1, Bruce T Hope1 & Yavin Shaham1

  1. The authors are at the Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, 5500 Nathan Shock Drive, Baltimore, Maryland 21224, USA. e-mail:

Addicts report that opiate drugs lose their rewarding effects over time, but the molecular mechanisms underlying this effect are unknown. A study now reports that tolerance to morphine reward in rats is due to downregulation of IRS2-Akt signaling in the ventral tegmental area (VTA), the cell body region of the mesolimbic dopamine reward system.