AUTHOR=Sircar Ratna 

TITLE=Behavioral changes and dendritic remodeling of hippocampal neurons in adolescent alcohol-treated rats

JOURNAL=Advances in Drug and Alcohol Research

VOLUME=Volume 3 - 2023

YEAR=2023

URL=https://www.frontierspartnerships.org/journals/advances-in-drug-and-alcohol-research/articles/10.3389/adar.2023.11158

DOI=10.3389/adar.2023.11158

ISSN=2674-0001

ABSTRACT=Objective: Earlier, we and others have reported that alcohol exposure in adolescent rat impaired performance of a spatial memory task in the Morris water maze.  The goal of the present study was to investigate the effects of adolescent alcohol treatment on hippocampus-dependent and hippocampus-independent memories. The study also looked at structural changes in CA1 hippocampal neurons in adolescent alcohol-treated rats.  Methods: Adolescent Sprague Dawley rats were administered with several doses of alcohol or vehicle either before training or after training (pre-testing).  Groups of alcohol-treated and control rats were trained in the fear conditioning paradigm, and 24 hours later tested for contextual fear conditioning and cued fear memory.  Randomly selected hippocampal sections from alcohol- and vehicle-treated rats were subjected to rapid Golgi staining, and CA1 pyramidal neurons were selected at random for analyses of dendritic branching and dendritic spine density. Results: Alcohol dose-dependently attenuated acquisition of contextual fear conditioning, but did not affect acquisition of amygdala-associated cued fear.  Alcohol did not alter either contextual or cued fear memory when administered after training.  CA1 pyramidal neurons in alcohol exposed rats showed reduced basilar tree branching and less complex dendritic arborization.  Conclusions: In adolescent rat, alcohol specifically impaired hippocampal learning but not amygdala-associated cued fear memory. CA1 hippocampal pyramidal neurons in alcohol-treated rats had fewer basilar dendritic branching. Together, these data suggest that adolescent alcohol exposure produces changes in the neuronal organization of the hippocampus, and these changes are associated with impairments in the relatively hippocampus-dependent memory formation.