Changes in dendritic spine density in the nucleus accumbens do not underlie ethanol sensitization.
Behavioral sensitization to various drugs of abuse has been shown to change dendritic spine density and/or morphology of nucleus accumbens (NAc) medium spiny neurons, an effect seen across drug classes. However, is it not known whether behavioral sensitization to ethanol (EtOH) is also associated with structural changes in this region. Here we compared dendritic spine density and morphology between mice showing High vs. Low levels of EtOH sensitization and found that high levels of EtOH sensitization were not associated with changes in dendritic spine density or spine type. Unexpectedly, however, a significant increase in the density of stubby-type spines was seen in mice that were resistant to sensitization. Since the presence of this spine type has been associated with long-term depression and cognitive/learning deficits this may explain why these mice fail to sensitize and why they show poor performance in conditioning tasks, as previously shown. A possible causal role for structural plasticity in behavioral sensitization to various drugs has been debated. In the case of EtOH sensitization, our results suggest that drug-induced changes in structural plasticity in the accumbens neurons may not be the cause of sensitized behavior.
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.|Behavioural Neurobiology Laboratory, Campbell Family Mental Health Research Institute, CAMH, Toronto, Ontario, Canada.
Christina N
CN
Nona
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
Marie Kristel
MK
Bermejo
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
Amy J
AJ
Ramsey
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.|Behavioural Neurobiology Laboratory, Campbell Family Mental Health Research Institute, CAMH, Toronto, Ontario, Canada.|Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.|Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
José N
JN
Nobrega
D000818:Animals; D049229:Dendritic Spines / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D051379:Mice; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D000431:Ethanol
ethanol; locomotor sensitization; nucleus accumbens; spine density