title: Anabolic-androgenic steroids decrease dendritic spine density in the nucleus accumbens of male rats.
abstract: Recent studies have demonstrated that anabolic-androgenic steroids (AAS) modify cognitive processes such as decision making and behavioral flexibility. However, the neural mechanisms underlying these AAS-induced cognitive changes remain poorly understood. The mesocorticolimbic dopamine (DA) system, particularly the nucleus accumbens (Acb), is important for reward, motivated behavior, and higher cognitive processes such as decision making. Therefore, AAS-induced plasticity in the DA system is a potential structural substrate for the observed cognitive alterations. High doses of testosterone (the most commonly-used AAS) increase dendritic spine density in limbic regions including the amygdala and hippocampus. However, effects on Acb are unknown. This was the focus of the present study. Adolescent male Long-Evans rats were treated chronically for 8weeks with high-dose testosterone (7.5mg/kg in water with 13% cyclodextrin) or vehicle sc. Brains were stained by Golgi-Cox to analyze neuronal morphology in medium spiny neurons of the shell region of Acb (AcbSh). Eightweeks of testosterone treatment significantly decreased spine density in AcbSh compared to brains of vehicle-treated rats (F1,14=5.455, p<0.05). Testosterone did not significantly affect total spine number, dendritic length, or arborization measured by Sholl analysis. These results show that AAS alter neuronal morphology in AcbSh by decreasing spine density throughout the dendritic tree, and provides a potential mechanism for AAS to modify cognition and decision-making behavior.
authors.affiliation: Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90033, USA. Electronic address: kwallin@usc.edu.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Wallin-Miller
authors.affiliation: Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA. Electronic address: lir@usc.edu.
authors.forename: Grace
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA; Department of Pharmaceutical Biosciences, Uppsala University, Sweden.
authors.forename: Diana
authors.initials: D
authors.lastname: Kelishani
authors.affiliation: Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA. Electronic address: riw@usc.edu.
authors.forename: Ruth I
authors.initials: RI
authors.lastname: Wood
mesh_terms: D000704:Analysis of Variance; D000728:Androgens / Q000633:toxicity*; D000818:Animals; D048429:Cell Size / Q000187:drug effects; D049229:Dendritic Spines / Q000187:drug effects* / Q000473:pathology; D004195:Disease Models, Animal; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000473:pathology; D020318:Rats, Long-Evans; D019966:Substance-Related Disorders / Q000473:pathology*; D013739:Testosterone / Q000633:toxicity*
chemical_list: D000728:Androgens; D013739:Testosterone
keywords: anabolic agents; dendritic spine density; medium spiny neurons; nucleus accumbens; testosterone