title: Adolescent mice are more vulnerable than adults to single injection-induced behavioral sensitization to amphetamine.
abstract: Drug-induced behavioral sensitization in rodents has enhanced our understanding of why drugs acquire increasing motivational and incentive value. Compared to adults, human adolescents have accelerated dependence courses with shorter times from first exposure to dependence. We compared adolescent and adult mice in their ability to develop behavioral sensitization to amphetamine following a single injection. Adult (90-day-old) and adolescent (45-day-old) male Swiss mice received an acute intraperitoneal injection of saline or amphetamine (1.0, 2.0 or 4.0 mg/kg). Seven days later, half of the mice from the saline group received a second injection of saline. The remaining animals were challenged with 2.0 mg/kg amphetamine. Following all of the injections, mice were placed in activity chambers and locomotion was quantified for 45 min. The magnitude of both the acute and sensitized locomotor stimulatory effect of amphetamine was higher in the adolescent mice. Previous experience with the test environment inhibited the acute amphetamine stimulation in both adolescent and adult mice, but facilitated the detection of elevated spontaneous locomotion in adolescent animals. These results support the notion that the adolescent period is associated with an increased risk for development of drug abuse. Additionally, they indicate a complex interaction between the environmental novelty, adolescence and amphetamine.
authors.affiliation: Department of Pharmacology, Universidade Federal de São Paulo, R. Botucatu, 862, Ed. Leal Prado, 1° andar, 04023062, São Paulo, SP, Brazil.
authors.forename: Sonia R
authors.initials: SR
authors.lastname: Kameda
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Fukushiro
authors.forename: Thaís F
authors.initials: TF
authors.lastname: Trombin
authors.forename: Roberta
authors.initials: R
authors.lastname: Procópio-Souza
authors.forename: Camilla L
authors.initials: CL
authors.lastname: Patti
authors.forename: André W
authors.initials: AW
authors.lastname: Hollais
authors.forename: Mariana B
authors.initials: MB
authors.lastname: Calzavara
authors.forename: Vanessa C
authors.initials: VC
authors.lastname: Abílio
authors.forename: Rosana A
authors.initials: RA
authors.lastname: Ribeiro
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Vânia
authors.initials: V
authors.lastname: D'Almeida
authors.forename: Roberto
authors.initials: R
authors.lastname: Frussa-Filho
mesh_terms: D000293:Adolescent; D000328:Adult; D000661:Amphetamine / Q000008:administration & dosage*; D019969:Amphetamine-Related Disorders / Q000209:etiology* / Q000523:psychology*; D000818:Animals; D016739:Behavior, Addictive / Q000503:physiopathology / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology*; D004195:Disease Models, Animal; D006801:Humans; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D012741:Sexual Maturation / Q000502:physiology*
chemical_list: D000661:Amphetamine