Cocaine craving during protracted withdrawal requires PKCε priming within vmPFC.

TitleCocaine craving during protracted withdrawal requires PKCε priming within vmPFC.
Publication TypeJournal Article
Year of Publication2017
AuthorsMiller BW, Wroten MG, Sacramento AD, Silva HE, Shin CB, Vieira PA, Ben-Shahar O, Kippin TE, Szumlinski KK
JournalAddict Biol
Volume22
Issue3
Pagination629-639
Date Published2017 May
ISSN1369-1600
KeywordsAnimals, Behavior, Animal, Cocaine, Cocaine-Related Disorders, Craving, Disease Models, Animal, Dopamine Uptake Inhibitors, Drug-Seeking Behavior, Immunoblotting, Male, Prefrontal Cortex, Protein Kinase C-epsilon, Rats, Rats, Sprague-Dawley, Substance Withdrawal Syndrome
Abstract

In individuals with a history of drug taking, the capacity of drug-associated cues to elicit indices of drug craving intensifies or incubates with the passage of time during drug abstinence. This incubation of cocaine craving, as well as difficulties with learning to suppress drug-seeking behavior during protracted withdrawal, are associated with a time-dependent deregulation of ventromedial prefrontal cortex (vmPFC) function. As the molecular bases for cocaine-related vmPFC deregulation remain elusive, the present study assayed the consequences of extended access to intravenous cocaine (6 hours/day; 0.25 mg/infusion for 10 day) on the activational state of protein kinase C epsilon (PKCε), an enzyme highly implicated in drug-induced neuroplasticity. The opportunity to engage in cocaine seeking during cocaine abstinence time-dependently altered PKCε phosphorylation within vmPFC, with reduced and increased p-PKCε expression observed in early (3 days) and protracted (30 days) withdrawal, respectively. This effect was more robust within the ventromedial versus dorsomedial PFC, was not observed in comparable cocaine-experienced rats not tested for drug-seeking behavior and was distinct from the rise in phosphorylated extracellular signal-regulated kinase observed in cocaine-seeking rats. Further, the impact of inhibiting PKCε translocation within the vmPFC using TAT infusion proteins upon cue-elicited responding was determined and inhibition coinciding with the period of testing attenuated cocaine-seeking behavior, with an effect also apparent the next day. In contrast, inhibitor pretreatment prior to testing during early withdrawal was without effect. Thus, a history of excessive cocaine taking influences the cue reactivity of important intracellular signaling molecules within the vmPFC, with PKCε playing a critical role in the manifestation of cue-elicited cocaine seeking during protracted drug withdrawal.

DOI10.1111/adb.12354
Alternate JournalAddict Biol
PubMed ID26769453
PubMed Central IDPMC4945488
Grant ListR01 DA024038 / DA / NIDA NIH HHS / United States
R01 DA027525 / DA / NIDA NIH HHS / United States