Administration of CRF1 antagonists systemically reversed the increased self-administration of cocaine associated with extended access, and this reversal was at antagonist doses that were lower than those that decreased short-access self-administration (Specio et al., 2008). Here, rats allowed 6 h access to cocaine showed an increase in cocaine intake over time, whereas 1 h access rats remained stable. Two different CRF1 antagonists blocked cocaine self-administration in the long-access rats at doses lower than those that blocked cocaine self-administration in short-access rats (Specio et al., 2008).
