Elevated levels of impulsivity and reduced place conditioning with d-amphetamine: two behavioral features of adolescence in mice.
Human adolescents may have experience with easily available psychoactive drugs. Impulsivity and/or peculiarities in reward systems may play a role. These variables were studied in adolescent (Postnatal Day [PND] 30-49) and adult (PND > 60) CD-1 mice. In Experiment 1 (impulsivity), food-restricted mice were tested in operant chambers with 2 nose-poking holes that delivered 1 food pellet immediately or 5 pellets after a delay, respectively. Delay length was increased over days (0-100 s). Adolescent mice showed a shift to the left in the intolerance-delay curve, as well as enhanced demanding when nose-poking was not reinforced. In Experiment 2 (place conditioning with d-amphetamine at 0.0. 1.0, 2.0, 3.3, or 5.0 mg/kg for 3 days), adolescent mice showed no reliable evidence of place conditioning when compared with adults. Hence, 2 main features of adolescence were elevated impulsivity and restlessness, and low (or absent) rewarding efficacy of amphetamine.
Adriani
Walter
W
Section of Behavioural Pathophysiology, Laboratorio Fisiopatologia O.S., Istituto Superiore di Sanità, Rome, Italy.
Laviola
Giovanni
G
D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D000367:Age Factors; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003216:Conditioning, Operant; D003913:Dextroamphetamine / Q000494:pharmacology*; D005260:Female; D005508:Food Deprivation; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology*; D008297:Male; D051379:Mice; D023421:Models, Animal; D019966:Substance-Related Disorders
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine