Opioid use produces enduring associations between drug reinforcement/euphoria and discreet or diffuse cues in the drug-taking environment. These powerful associations can trigger relapse in individuals recovering from opioid use disorder… Click to show full abstract
Opioid use produces enduring associations between drug reinforcement/euphoria and discreet or diffuse cues in the drug-taking environment. These powerful associations can trigger relapse in individuals recovering from opioid use disorder (OUD). Here, we sought to determine whether the epigenetic enzyme, histone deacetylase 5 (HDAC5), regulates relapse-associated behavior in an animal model of OUD. We examined the effects of nucleus accumbens (NAc) HDAC5 on both heroin- and sucrose-seeking behaviors using operant self-administration paradigms. We utilized cre-dependent viral-mediated approaches to investigate the cell-type-specific effects of HDAC5 on heroin-seeking behavior, gene expression, and medium spiny neuron (MSN) cell and synaptic physiology. We found that NAc HDAC5 functions during the acquisition phase of heroin self-administration to limit future relapse-associated behavior. Moreover, overexpressing HDAC5 in the NAc suppressed context-associated and reinstated heroin-seeking behaviors, but it did not alter sucrose seeking. We also found that HDAC5 functions within dopamine D1 receptor-expressing MSNs to suppress cue-induced heroin seeking, and within dopamine D2 receptor-expressing MSNs to suppress drug-primed heroin seeking. Assessing cell-type-specific transcriptomics, we found that HDAC5 reduced expression of multiple ion transport genes in both D1- and D2-MSNs. Consistent with this observation, HDAC5 also produced firing rate depression in both MSN classes. These findings revealed roles for HDAC5 during active heroin use in both D1- and D2-MSNs to limit distinct triggers of drug-seeking behavior. Together, our results suggest that HDAC5 might limit relapse vulnerability through regulation of ion channel gene expression and suppression of MSN firing rates during active heroin use.
               
Click one of the above tabs to view related content.