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Differential changes in accumbens shell and core dopamine in behavioral sensitization to nicotine
1Department of Toxicology and CNR Center for Neuropharmacology, University of Cagliari, Viale Diaz 182, 09126, Cagliari, Italy.
European Journal of Pharmacology
|January 29, 2000
Summary
Repeated nicotine exposure sensitizes rats to its effects. This study reveals nicotine alters dopamine transmission differently in the nucleus accumbens shell and core following sensitization.
Area of Science:
- Neuroscience
- Pharmacology
- Behavioral Science
Background:
- Repeated nicotine administration induces behavioral sensitization in rats.
- Nicotine also enhances dopamine transmission in the mesolimbic system.
Purpose of the Study:
- To investigate the relationship between nicotine-induced locomotor sensitization and dopamine transmission changes in the nucleus accumbens (NAc) shell and core.
- To determine if dopamine release patterns in NAc subregions differ following chronic nicotine exposure.
Main Methods:
- Rats received daily nicotine (0.4 mg/kg) or saline injections for 5 days.
- Twenty-four hours after the last injection, dopamine levels were measured using microdialysis in the NAc shell and core.
- Locomotor activity was assessed after a nicotine challenge dose.
Main Results:
- Behavioral sensitization to nicotine was observed.
- Nicotine challenge resulted in reduced dopamine transmission in the NAc shell.
- Conversely, nicotine challenge led to increased dopamine transmission in the NAc core.
Conclusions:
- Nicotine-induced behavioral sensitization is linked to differential modulation of dopamine transmission in the NAc shell and core.
- These findings suggest distinct roles for NAc subregions in the neuroadaptations underlying nicotine dependence.