Left/right nigrostriatal asymmetry in susceptibility to neurotoxic dopamine depletion with 6-hydroxydopamine in rats

Male Sprague-Dawley rats were investigated for the existence of a left/right hemispheric population asymmetry in the extent of striatal dopamine depletion following unilateral lesions with 6-hydroxydopamine (6-OHDA) in the left or right substantial nigra. Four doses of 6-OHDA were employed (with left and right lesion groups at each dose). Analysis of striatal dopamine depletion revealed significant main effects not only for dose of 6-OHDA, but also for side of lesion, with right-lesioned rats having greater dopamine depletion across doses. In a group of non-lesioned rats, randomly selected from this population, striatal dopamine turnover showed a significant right-sided bias. It is suggested that the latter functional asymmetry may have been responsible for the neurotoxic depletion asymmetry seen in lesioned animals, and that side of lesion should be considered when attempting to produce consistent and maximal dopamine depletion in large scale studies with the unilateral 6-OHDA lesion paradigm.