Electrolytic lesions of the nucleus accumbens core (but not the medial shell) and the basolateral amygdala enhance context-specific locomotor sensitization to nicotine in rats.
We previously demonstrated that lesions of the nucleus accumbens (NAc) core enhanced locomotion and locomotor sensitization to repeated injections of nicotine in rats (Kelsey & Willmore, 2006). In this study, we compared the effects of separate lesions of the NAc core, NAc medial shell, and basolateral amygdala on context-specific locomotor sensitization to repeated injections of 0.4 mg/kg nicotine. Electrolytic lesions of the NAc core increased locomotion, and lesions of the core (but not the shell) and the basolateral amygdala enhanced context-specific locomotor sensitization by enhancing the development of sensitization in paired rats and decreasing expression in unpaired rats relative to sham-operated rats when challenged with an injection of 0.4 mg/kg nicotine in the locomotor chambers. These data are consistent with findings that the NAc core and the basolateral amygdala share a variety of behavioral functions and anatomical connections. The findings that lesions of these structures enhance context-specific locomotor sensitization while typically impairing other reward-related behaviors also indicate that the processes underlying locomotor sensitization and reward are not identical.
Kelsey
John E
JE
Program in Neuroscience, Department of Psychology, Bates College, Lewiston, ME 04240, USA. jkelsey@bates.edu
Gerety
Lyle P
LP
Guerriero
Rejean M
RM
D000679:Amygdala / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D004572:Electrolysis; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans
D018722:Nicotinic Agonists; D009538:Nicotine