title: Periadolescent nicotine administration produces enduring changes in dendritic morphology of medium spiny neurons from nucleus accumbens.
abstract: The objective of the current study was to examine how periadolescent nicotine exposure affects dendritic morphology of medium spiny neurons from the nucleus accumbens shell. Male Long-Evans hooded rats were chronically administered nicotine or saline for a period extending from postnatal day 22 (p22) to p69. Nicotine and saline administration was via subcutaneously implanted osmotic pumps. At p144, 75 days after conclusion of nicotine administration, brains were processed for Golgi-Cox staining. Medium spiny neurons from the nucleus accumbens shell were digitally reconstructed. It was found that neurons from nicotine-treated animals possessed significantly longer dendrites and a greater number of dendritic segments than control animals. A branch order analysis indicated that differences in dendritic length and segment number were most pronounced in third and fourth order segments. A subsequent behavioral experiment suggests that the observed anatomical changes are associated with enduring psychomotor differences. These findings indicate that periadolescent exposure to nicotine can result in long-lasting structural changes in the nucleus accumbens shell and are consistent with behavioral data suggesting that adolescent nicotine exposure may result in vulnerability to nicotine addiction in adulthood.
authors.affiliation: Department of Psychology, George Mason University, 4400 University Drive, David King Hall Mail Stop 3F5, Fairfax, VA 22030, USA. cmcdona3@gmu.edu
authors.forename: Craig G
authors.initials: CG
authors.lastname: McDonald
authors.forename: Vernon K
authors.initials: VK
authors.lastname: Dailey
authors.forename: Hadley C
authors.initials: HC
authors.lastname: Bergstrom
authors.forename: Tracey L
authors.initials: TL
authors.lastname: Wheeler
authors.forename: Amy K
authors.initials: AK
authors.lastname: Eppolito
authors.forename: Laura N
authors.initials: LN
authors.lastname: Smith
authors.forename: Robert F
authors.initials: RF
authors.lastname: Smith
mesh_terms: D000367:Age Factors; D000818:Animals; D048430:Cell Shape / Q000187:drug effects / Q000502:physiology; D003712:Dendrites / Q000187:drug effects* / Q000473:pathology; D004195:Disease Models, Animal; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000254:growth & development / Q000473:pathology; D051381:Rats; D020318:Rats, Long-Evans; D012201:Reward; D012307:Risk Factors; D012741:Sexual Maturation; D014029:Tobacco Use Disorder / Q000473:pathology / Q000503:physiopathology
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine