β-Arrestin-biased β-adrenergic signaling promotes extinction learning of cocaine reward memory

Extinction learning of cocaine-associated contextual cues can help prevent cocaine addicts from relapsing. Pharmacological manipulation of β-adrenergic receptor (β-AR) during extinction learning is being developed as a potential strategy to treat drug addiction. We demonstrated that the extinction learning of cocaine-associated memory was mediated by β-arrestin2-biased but not heterotrimeric guanine nucleotide-binding protein (G protein)-dependent β-adrenergic signaling. We found that administration of the nonbiased β-AR antagonist propranolol, but not the G protein-biased β-AR antagonist carvedilol, blocked extinction learning of cocaine-conditioned place preference and the associated ERK activation in the infralimbic prefrontal cortex. Overexpression of β-arrestin2 in the infralimbic prefrontal cortex promoted extinction learning, which was blocked by propranolol. Knockout of β-arrestin2 in the infralimbic prefrontal cortex, specifically in excitatory neurons, impaired extinction learning of cocaine-conditioned place preference, which was not rescued by carvedilol. β-Arrestin2 signaling in infralimbic excitatory neurons was also required for the extinction learning in the cocaine self-administration model. Our results suggest that β-arrestin-biased β-adrenergic signaling in the infralimbic prefrontal cortex regulates extinction learning of cocaine-associated memories and could be therapeutically targeted to treat addiction.