Circadian genes in the medial accumbal shell (mNAcSh) region regulate binge alcohol consumption. Here, we investigated if antisense-induced knockdown of major circadian genes (Per1, Per2, and NPAS2) in the mNAcSh of mice exposed to intermittent access two-bottle choice (IA2BC) paradigm modulates the expression of histone deacetylase-2 (HDAC-2) and CREB-binding protein (CBP), key epigenetic modifiers associated with withdrawal-associated behaviors such as anxiety. Adult male C57BL/6J mice (N = 28), surgically implanted with bilateral guide cannulas above the mNAcSh, were chronically (4 weeks) exposed to alcohol (20% v/v) or saccharin (0.03%) via IA2BC paradigm. In the fourth week, a mixture of antisense (AS-ODNs; N = 14/group) or nonsense (NS-ODNs; N = 14/group) oligodeoxynucleotides against circadian genes were bilaterally infused into the mNAcSh. Subsequently, alcohol/saccharin consumption and preference were measured followed by euthanization of animals and verification of microinjection sites by visual inspection and the expression of HDAC-2 and CBP by using RT-PCR along with the verification of antisense-induced downregulation of circadian genes in the mNAcSh. As compared with NS-ODNs, AS-ODNs infusion significantly attenuated the alcohol-induced increase in HDAC-2 and reduction in CBP expression in the mNAcSh along with a significant reduction in alcohol consumption and preference. No significant effect was observed on either saccharin consumption or preference. Our results suggest that circadian genes in the mNAcSh may have a causal to play in mediating epigenetic changes observed after chronic alcohol consumption.
Keywords: CBP; HDAC-2; alcohol use disorder; circadian genes; neuronal PAS Domain Protein 2; nucleus accumbens; period.
© 2021 International Society for Neurochemistry.