Accumbens Homer2 overexpression facilitates alcohol-induced neuroplasticity in C57BL/6J mice.

TitleAccumbens Homer2 overexpression facilitates alcohol-induced neuroplasticity in C57BL/6J mice.
Publication TypeJournal Article
Year of Publication2008
AuthorsSzumlinski KK, Ary AW, Lominac KD, Klugmann M, Kippin TE
JournalNeuropsychopharmacology
Volume33
Issue6
Pagination1365-78
Date Published2008 May
ISSN0893-133X
KeywordsAlcohol Drinking, Animals, Behavior, Animal, Carrier Proteins, Central Nervous System Depressants, Conditioning, Operant, Ethanol, Gene Expression Regulation, Green Fluorescent Proteins, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Neuronal Plasticity, Nucleus Accumbens, Receptors, Metabotropic Glutamate, Reinforcement (Psychology), Time Factors, Transduction, Genetic
Abstract

Homer proteins are integral components of the postsynaptic density that are necessary for alcohol-induced neuroplasticity within the nucleus accumbens (NAC). In this report, we describe the effects of chronic alcohol consumption upon NAC Homer expression and investigate the functional consequences of mimicking the alcohol-induced changes in Homer expression vis-à-vis alcohol-induced changes in NAC neurochemistry and behavior. Chronic alcohol consumption under continuous access (3 months; daily intake approximately 11.2+/-1.5 g/kg/day) produced a robust increase in NAC Homer2 protein levels that was apparent at 2 days, 2 weeks, and 2 months following withdrawal from alcohol drinking. The increased Homer2 expression was accompanied by a less enduring elevation in total mGluR1 and NR2b levels that were evident at 2 days and 2 weeks but not at the 2-month time point. Mimicking the alcohol-induced increase in Homer2 levels by viral transfection of NAC neurons in alcohol-preferring C57BL/6J inbred mice enhanced behavioral output for alcohol reinforcement and increased alcohol intake under both preprandial and postprandial conditions. Moreover, NAC Homer2 overexpression facilitated the expression of an alcohol-conditioned place preference, as well as the development of motor tolerance. Finally, NAC Homer2 overexpression facilitated NAC glutamate and dopamine release following an acute alcohol injection and augmented alcohol-induced dopamine and glutamate sensitization, but did not affect NAC gamma-aminobutyric acid levels. Thus, an upregulation in NAC mGluR-Homer2-N-methyl-D-aspartic acid receptor signaling appears to be an important molecular adaptation to alcohol that promotes neuroplasticity facilitating motivational drive for alcohol and the development of alcoholism-related behaviors.

DOI10.1038/sj.npp.1301473
Alternate JournalNeuropsychopharmacology
PubMed ID17568396
Grant ListAA-0135017 / AA / NIAAA NIH HHS / United States
AA-015351 / AA / NIAAA NIH HHS / United States
AA-016650 / AA / NIAAA NIH HHS / United States