Nigrostriatal Damage is Required for Induction of Dyskinesias by l-DOPA in Squirrel Monkeys.
Boyce, S.; Rupniak, N. M. J.; Steventon, M. J.; Iversen, S. D.
[Article] Clinical Neuropharmacology. 13(5):448-458, October 1990.

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Summary: We examined the ability of l-DOPA to induce dyskinesias in MPTP-treated and normal squirrel monkeys to establish whether the underlying neuropathology associated with parkinsonism is an absolute requirement or merely promotes the development of drug-induced dyskinesias. Administration of l-DOPA (5-40 mg/kg p.o., following a 60 min pretreatment with carbidopa 2.5-20 mg/kg p.o.) induced a range of dopamine-mediated behaviours including locomotor activity, stereotyped scratching, and climbing in both lesioned and nonlesioned animals. However, the dose-response curves showed a marked (three- to fourfold) shift to the left in lesioned animals, indicating behavioural supersensitivity. In contrast, l-DOPA-induced dyskinesias were only observed in MPTP-treated monkeys. Doses required for induction of dyskinesias were lower than those required to induce climbing. These findings provide further evidence that nigrostriatal damage is essential for the genesis of l-DOPA-induced dyskinesias.

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