Histone Acetylation in the Nucleus Accumbens Shell Modulates Ethanol-Induced Locomotor Activity in DBA/2J Mice
Version of Record online: 4 AUG 2014
Copyright © 2014 by the Research Society on Alcoholism
Alcoholism: Clinical and Experimental Research
Volume 38, Issue 9, pages 2377–2386, September 2014
How to Cite
Sprow, G. M., Rinker, J. A. and Thiele, T. E. (2014), Histone Acetylation in the Nucleus Accumbens Shell Modulates Ethanol-Induced Locomotor Activity in DBA/2J Mice. Alcoholism: Clinical and Experimental Research, 38: 2377–2386. doi: 10.1111/acer.12502
- Issue online: 24 SEP 2014
- Version of Record online: 4 AUG 2014
- Manuscript Accepted: 20 MAY 2014
- Manuscript Received: 20 NOV 2013
- National Institutes of Health. Grant Numbers: AA019839, AA021611, AA013573, AA015148, AA022048
- Trichostatin A
A growing body of literature suggests that epigenetic mechanisms, including histone acetylation, may play key roles in drug abuse and the development of addiction. Experiments in this study were designed to investigate the role of histone acetylation in ethanol (EtOH)-induced locomotor sensitization.
Immunohistochemical, Western blotting, and site-directed pharmacological techniques were used to explore the roles of histone acetylation at histone H3 (acH3K9) in both the expression of and acquisition of EtOH-induced locomotor sensitization. A commonly used sensitization protocol, in which animals were exposed to repeated injections of a low dose of EtOH while in their home cage, was used to examine this behavioral phenomenon. Additionally, site-directed administration of the histone deacetylase inhibitor (HDACi) Trichostatin A (TSA), in the absence of repeated EtOH injections, was used to examine the role of hyperacetylation in the nucleus accumbens (NAC) shell in EtOH-induced locomotor sensitization.
Sensitized mice displayed elevated acH3K9 immunoreactivity (IR) localized to the shell of the NAC. This augmentation in acH3K9 IR was confirmed, in a separate experiment, using Western blot analyses. Next, repeated intra-accumbal infusions of TSA, in the absence of repeated EtOH injections, were sufficient to induce an augmented locomotor response to a later injection of a low dose (2.0 g/kg, intraperitoneally) of EtOH, indicative of cross-sensitization to this locomotor stimulation between TSA and EtOH. Finally, a local infusion of TSA into the shell of the accumbens was also associated with a significant increase in acH3K9 IR within this region.
Together, the present observations suggest that histone acetylation, particularly within the shell of the NAC, is important for the development and expression of EtOH-induced locomotor sensitization.