title: Cocaine-induced dendritic remodeling occurs in both D1 and D2 dopamine receptor-expressing neurons in the nucleus accumbens.
abstract: Repeated exposure to cocaine can induce persistent alterations in the brain's reward system, including increases in the number of dendrites and spine density on medium-sized spiny neurons (MSNs) in the nucleus accumbens (NAc). The structural remodeling of dendrites and spines in the NAc is thought to play a critical role in cocaine addiction. MSNs in the NAc can be classified by expression of either D1 or D2 dopamine receptors, which are localized to the direct and indirect pathway, respectively. It is unknown whether the dendritic changes induced by repeated cocaine treatment occur in MSNs of the direct or indirect pathway. Because the traditional Golgi-Cox impregnation of neurons precludes identifying particular subpopulations of MSNs, we performed dendritic morphology analysis after biocytin-labeling and Golgi-Cox impregnation. We found that the biocytin staining MSNs showed higher dendritic spine density and higher number of dendrites than that in Golgi impregnation group. In addition, we found that the increasing spine density induced by repeated cocaine treatment in female mice was higher than that in male mice. Next we used biocytin staining and dynorphin/D2 receptor colocalization to determine which cell type(s) displayed dendritic changes after repeated cocaine treatment. We found that cocaine-induced changes in dendritic parameters occurred in MSNs of both the direct (D1-expressing) and indirect (D2-expressing) pathways.
authors.affiliation: Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Nuyun
authors.initials: N
authors.lastname: Liu
authors.forename: Kangrong
authors.initials: K
authors.lastname: Lu
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Gu
authors.forename: Fukun
authors.initials: F
authors.lastname: Guo
authors.forename: Shengli
authors.initials: S
authors.lastname: An
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D004396:Coloring Agents; D003712:Dendrites / Q000187:drug effects* / Q000648:ultrastructure; D049229:Dendritic Spines; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D059290:Dopaminergic Neurons / Q000187:drug effects* / Q000648:ultrastructure; D004399:Dynorphins / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D008239:Lysine / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D051379:Mice; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects*; D017448:Receptors, Dopamine D2 / Q000187:drug effects*; D050637:Receptors, Dopamine D3 / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D004396:Coloring Agents; D018765:Dopamine Uptake Inhibitors; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D004399:Dynorphins; C013411:biocytin; D003042:Cocaine; D008239:Lysine