Evaluation of functional asymmetry in rats with dose-dependent lesions of dopaminergic nigrostriatal system using elevated body swing test.

Although drug-induced rotational behavior has conventionally been used for the assessment of functional asymmetry in 6-hydroxydopamine (OHDA)-lesioned rats, a pure behavioral test that can evaluate animals with dose-dependent lesions of the dopaminergic nigrostriatal system in a drug-free state may better reflect a more natural response following lesion. In this study, elevated body swing test (EBST) was used for evaluation of rats with varying lesions of the dopaminergic nigrostriatal system. For this purpose, rats received intrastriatal injection of 8 (L1), 12 (L2), 16 (L3), and 20 (L4) microg of the neurotoxin 6-OHDA (dissolved in 5 microl of saline-ascorbate). Apomorphine-induced rotational and drug-free elevated body swing behaviors were evaluated before and at different time points after the experiment. The results showed that although there is a significant trend for contralateral rotations and drug-free swings in lesioned rats as compared to sham-operated group, however, there were no significant differences between the L1 and L2 and between the L3 and L4 groups regarding EBST. Therefore, EBST may be valuable for behavioral analysis of rats with mild and/or severe damage of the dopaminergic nigrostriatal system.