HSP90AA1 and opiate dependence: An in vitro study found that Hsp90 inhibition decreased cAMP superactivation, a marker for opioid dependence (Koshimizu et al., 2010); supporting these findings, an in vivo mouse study found that injection of Hsp90 inhibitor reduced the somatic signs of morphine withdrawal (Abul-Husn et al., 2011).