ABSTRACT
Background: Nicotinic and dopaminergic systems influence anxiety behavior. Furthermore, the interaction between nicotine and dopamine D1 receptors has been demonstrated in modulation of some behaviors
Objective: To investigate the involvement of dorsal hippocampus dopaminergic D1 receptor in the nicotine effects on anxiety behavior
Methods: This was an experimental study carried out at Tehran Institute of Cognitive Sciences in2009. Initially, 190 mice in 10-member groups were placed in a stereotaxic apparatus and twocannulae placed in the CA1 region of hippocampus. Later, the effects of dopaminergic D1 receptors agonist [SKF38393] and antagonist [SCH23390] on nicotine anxiogenic effects in mice were measured using hole-board test of anxiety. Data were analyzed using one-way analysis of variance followed by Dunnett's test
Findings: Nicotine [0.5 mg/kg] produced anxiogenic effect [P<0.001]. Intra-CA1 injections of ineffective doses of SCH23390 reversed the anxiogenic effects induced by nicotine [P<0.001]. Furthermore, co-administration of ineffective dose of SKF38393 plus ineffective dose of nicotine increased the anxiogenic effect of nicotine [P<0.001]. Locomotion activity was unchanged when no drug was administered
Conclusion: The results indicated that dopamine D1 receptors of the dorsal hippocampus have modulatory role in the anxiogenic response induced by nicotine