cAMP response element binding protein (CREB) signaling is involved in the heroin reward, but whether the CREB signaling is involved in the incubation of heroin-seeking remains unknown. Here we aim to explore the expression of p-CREB and the p-ERK, an upstream molecular of CREB, in the nucleus accumbens (NAc) in the incubation of heroin-seeking induced by cue after withdrawal. First, rats were trained to self-administer heroin for 14 days, and then assessed heroin-seeking induced by context cue (CC)or by conditioned cues (CS)after 1 or 14 d withdrawal. We found that the active responses induced by CC or CS was higher after 14 d withdrawal than that after 1 d withdrawal, and the extent increased was more significant by CS than that by CC. Meanwhile, the expression of p-ERK decreased significantly when rats exposed to the CS, and decreased more after 14 d withdrawal. In contrast, reduction of the expression of p-CREB was more obvious with exposure to CS after 14 d withdrawal. Furthermore, microinjection of rolipram into the NAc decreased the heroin-seeking behavior induced by CS after 14 d withdrawal, which was correlated to an enhancement in the expression of p-CREB in the NAc. These findings suggest that the inactivation of CREB and ERK may be involved in the incubation of heroin-seeking induced by cues after prolonged withdrawal.
Keywords: Addiction; Opioid; Phosphodiesterase-4; Transcription factor; cAMP.
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