Activation of GSK3? induced by recall of cocaine reward memories is dependent on GluN2A/B NMDA receptor signaling.

ABSTRACT: Glycogen synthase kinase-3? (GSK3?) is a critical regulator of the balance between long-term depression and long-term potentiation which is essential for learning and memory. Our previous study demonstrated that GSK3? activity is highly induced during cocaine memory reactivation, and that reconsolidation of cocaine reward memory is attenuated by inhibition of GSK3?. NMDA receptors and protein phosphatase 1 (PP1) are activators of GSK3?. Thus, this study investigated the roles of NMDA receptor subtypes and PP1in the reconsolidation of cocaine contextual reward memory. Cocaine contextual memories were established and evaluated using cocaine conditioned place preference methods. The regulation of GSK3? activity in specific brain areas was assessed by measuring its phosphorylation state using immunoblot assays. Mice underwent cocaine place conditioning for 8 days and were tested for place preference on day 9. Twenty-four hours later, mice were briefly confined to the compartment previous paired with cocaine to reactivate cocaine-associated memories. Administration of the GluN2A- and GluN2B-NMDA receptor antagonists, NVP-AAM077 and ifenprodil, respectively, immediately following recall abrogated an established cocaine place preference, while preventing the activation of GSK3? in the amygdala, nucleus accumbens, and hippocampus during cocaine memory reactivation. PP1 inhibition with okadaic acid also blocked the activation of GSK3? and attenuated a previously established cocaine place preference. These findings suggest that the dephosphorylation of GSK3? that occurred upon activation of cocaine-associated reward memories may be initiated by the activation of PP1 during the induction of NMDA receptor-dependent reconsolidation of cocaine mnemonic traces. Moreover, the importance of NMDA receptors and PP1 in reconsolidation of cocaine memory makes them potential therapeutic targets in treatment of cocaine use disorder and prevention of relapse.

SUBMITTER: Shi X 

PROVIDER: S-EPMC6788955 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature