Differential changes in accumbens shell and core dopamine in behavioral sensitization to nicotine

Repeated treatment with nicotine has been shown to sensitize rats to its lo comotor stimulant effects and to its properties to stimulate mesolimbic dop amine transmission. We investigated the relationship between sensitization of nicotine induced locomotor stimulation and activation of dopamine transm ission in the nucleus accumbens shell and core. Rats were administered dail y for 5 days with 0.4 mg/kg s.c. of nicotine or with saline and 24 h later, dopamine was monitored by microdialysis in the shell and in the core of nu cleus accumbens and behavioral activity was scored after challenge with nic otine (0.4 mg/kg s.c.). Behavioral sensitization to nicotine was associated with a reduced response of dopamine transmission in the shell and with an increased one in the core of nucleus accumbens. (C) 2000 Elsevier Science B .V. All rights reserved.